Coordination Compounds · Chemistry · JEE Main

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MCQ (Single Correct Answer)

1

Match the LIST-I with LIST-II

LIST-I
(Complex/ Species)
LIST-II
(Shape & magnetic moment)
A. [Ni(CO)4]I. Tetrahedral, 2.8 BM
B. [Ni(CN)4]2–II. Square planar, 0 BM
C. [NiCl4]2–III. Tetrahedral, 0 BM
D. [MnBr4]2–IV. Tetrahedral, 5.9 BM

Choose the correct answer from the options given below:

JEE Main 2025 (Online) 8th April Evening Shift
2

The number of species from the following that are involved in sp3d2 hybridization is :

[Co(NH3)6]3+, SF6, [CrF6]3−, [CoF6]3−, [Mn(CN)6]3−, and [MnCl6]3−

JEE Main 2025 (Online) 8th April Evening Shift
3

Given below are two statements:

Statement I: A homoleptic octahedral complex, formed using monodentate ligands, will not show stereoisomerism.

Statement II: cis- and trans- platin are heteroleptic complexes of Pd.

In the light of the above statements, choose the correct answer from the options given below:

JEE Main 2025 (Online) 8th April Evening Shift
4

Match List - I with List - II.

List - I (Complex) List - II (Primary valency and Secondary valency)
(A) [Co(en)2Cl2]Cl (I) 3,    6
(B) [Pt(NH3)2Cl(NO2)] (II) 3,    4
(C) Hg [Co(SCN)4] (III) 2,    6
(D) [Mg (EDTA)]2− (IV) 2,    4

Choose the correct answer from the options given below :

JEE Main 2025 (Online) 7th April Evening Shift
5

The number of unpaired electrons responsible for the paramagnetic nature of the following complex species are respectively :

[Fe(CN)6]3−, [FeF6]3−, [CoF6]3−, [Mn(CN)6]3−

JEE Main 2025 (Online) 7th April Evening Shift
6

'X' is the number of acidic oxides among VO2, V2O3, CrO3, V2O5 and Mn2O7. The primary valency of cobalt in
[Co(H2NCH2CH2NH2)3]2(SO4)3 is Y. The value of X + Y is _________.

JEE Main 2025 (Online) 7th April Evening Shift
7

An octahedral complex having molecular composition $\mathrm{Co} \cdot 5 \mathrm{NH}_3 \cdot \mathrm{Cl}^2 . \mathrm{SO}_4$ has two isomers A and B. The solution of A gives a white precipitate with $\mathrm{AgNO}_3$ solution and the solution of B gives white precipitate with $\mathrm{BaCl}_2$ solution. The type of isomerism exhibited by the complex is,

JEE Main 2025 (Online) 7th April Morning Shift
8

' $X$ ' is the number of electrons in $t_{2 g}$ orbitals of the most stable complex ion among $\left[\mathrm{Fe}\left(\mathrm{NH}_3\right)_6\right]^{3+},\left[\mathrm{FeCl}_6\right]^{3-}, \quad\left[\mathrm{Fe}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]^{3-}$ and $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$. The nature of oxide of vanadium of the type $\mathrm{V}_2 \mathrm{O}_{\mathrm{X}}$ is :

JEE Main 2025 (Online) 4th April Evening Shift
9

The correct order of $\left[\mathrm{FeF}_6\right]^{3-},\left[\mathrm{CoF}_6\right]^{3-},\left[\mathrm{Ni}(\mathrm{CO})_4\right]$ and $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$ complex species based on the number of unpaired electrons present is:

JEE Main 2025 (Online) 4th April Evening Shift
10

Which one of the following complexes will have $\Delta_{\mathrm{o}}=0$ and $\mu=5.96$ B.M?

JEE Main 2025 (Online) 4th April Morning Shift
11

Number of stereoisomers possible for the complexes, $\left[\mathrm{CrCl}_3(\mathrm{py})_3\right]$ and $\left[\mathrm{CrCl}_2(\mathrm{ox})_2\right]^{3-}$ are respectively $(p y=$ pyridine,$o x=$ oxalate $)$

JEE Main 2025 (Online) 4th April Morning Shift
12

Identify the diamagnetic octahedral complex ions from below ;

A. $\left[\mathrm{Mn}(\mathrm{CN})_6\right]^{3-}$

B. $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}$

C. $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{4-}$

D. $\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)_3 \mathrm{~F}_3\right]$

Choose the correct answer from the options given below:

JEE Main 2025 (Online) 3rd April Evening Shift
13
The correct order of the complexes $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5\left(\mathrm{H}_2 \mathrm{O}\right)\right]^{3+}(\mathrm{A}),\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}(\mathrm{B}),\left[\mathrm{Co}(\mathrm{CN})_6\right]^{3-}(\mathrm{C})$ and $\left[\mathrm{CoCl}\left(\mathrm{NH}_3\right)_5\right]^{2+}(\mathrm{D})$ in terms of wavelength of light absorbed is
JEE Main 2025 (Online) 3rd April Morning Shift
14

$$ \text { Match the LIST-I with LIST-II } $$

LIST-I
(Molecules/ion)
LIST-II
(Hybridisation of central atom)
A. $$
\mathrm{PF}_5
$$
I $$
\mathrm{dsp}^2
$$
B $$
\mathrm{SF}_6
$$
II $$
\mathrm{sp}^3 \mathrm{~d}
$$
C $$
\mathrm{Ni}(\mathrm{CO})_4
$$
III $$
\mathrm{sp}^3 \mathrm{~d}^2
$$
D $$
\left[\mathrm{PtCl}_4\right]^{2-}
$$
IV $$
\mathrm{sp}^3
$$

$$ \text { Choose the correct answer from the options given below: } $$

JEE Main 2025 (Online) 3rd April Morning Shift
15
The type of hybridization and the magnetic property of $\left[\mathrm{MnCl}_6\right]^{3-}$ are,
JEE Main 2025 (Online) 2nd April Evening Shift
16
The d-orbital electronic configuration of the complex among $\left[\mathrm{Co}(\mathrm{en})_3\right]^{3+},\left[\mathrm{CoF}_6\right]^{3-}$, $\left[\mathrm{Mn}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$ and $\left[\mathrm{Zn}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$ that has the highest CFSE is :
JEE Main 2025 (Online) 2nd April Evening Shift
17

Given below are two statements :

Statement (I) : In octahedral complexes, when $\Delta_0<\mathrm{P}$ high spin complexes are formed. When $\Delta_0>P$ low spin complexes are formed.

Statement (II) : In tetrahedral complexes because of $\Delta_t

In the light of the above statements, choose the most appropriate answer from the options given below :

JEE Main 2025 (Online) 2nd April Morning Shift
18

Identify the homoleptic complexes with odd number of $d$ electrons in the central metal :

(A) $\left[\mathrm{FeO}_4\right]^{2-}$

(B) $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$

(C) $\left[\mathrm{Fe}(\mathrm{CN})_5 \mathrm{NO}\right]^{2-}$

(D) $\left[\mathrm{CoCl}_4\right]^{2-}$

(E) $\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)_3 \mathrm{~F}_3\right]$

Choose the correct answer from the options given below :

JEE Main 2025 (Online) 29th January Evening Shift
19

The calculated spin-only magnetic moments of $K_3[Fe(OH)_6]$ and $K_4[Fe(OH)_6]$ respectively are :

JEE Main 2025 (Online) 29th January Evening Shift
20

The correct increasing order of stability of the complexes based on $\Delta_0$ value is :

  1. I. $[\text{Mn}(\text{CN})_6]^{3-}$

  2. II. $[\text{Co}(\text{CN})_6]^{4-}$

  3. III. $[\text{Fe}(\text{CN})_6]^{4-}$

  4. IV. $[\text{Fe}(\text{CN})_6]^{3-}$
JEE Main 2025 (Online) 29th January Morning Shift
21

Match List - I with List - II.

List - I (Complex) List - II (Hybridisation & Magnetic characters)
(A) [MnBr4]2- (I) d2sp3 & diamagnetic
(B) [FeF6]3- (II) sp3d2 & paramagnetic
(C) [Co(C2O4)3]3- (III) sp3 & diamagnetic
(D) [Ni(CO)4] (IV) sp3 & paramagnetic

Choose the correct answer from the options given below :

JEE Main 2025 (Online) 29th January Morning Shift
22

Match List - I with List - II.

List - I (Complex) List - II (Hybridisation of central metal ion)
(A) [CoF6]3- (I) d2sp3
(B) [NiCl4]2- (II) sp3
(C) [Co(NH3)6]3+ (III) sp3d2
(D) [Ni(CN)4]2- (IV) dsp2
Choose the correct answer from the options given below:

JEE Main 2025 (Online) 28th January Evening Shift
23

The conditions and consequence that favours the $t_{2 \mathrm{~g}}{ }^3 \mathrm{e}_{\mathrm{g}}{ }^1$ configuration in a metal complex are :

JEE Main 2025 (Online) 24th January Evening Shift
24

When Ethane-1,2-diamine is added progressively to an aqueous solution of Nickel (II) chloride, the sequence of colour change observed will be:

JEE Main 2025 (Online) 24th January Evening Shift
25

One mole of the octahedral complex compound $\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}_3$ gives 3 moles of ions on dissolution in water. One mole of the same complex reacts with excess of $\mathrm{AgNO}_3$ solution to yield two moles of $\mathrm{AgCl}_{(\mathrm{s})}$. The structure of the complex is:

JEE Main 2025 (Online) 24th January Morning Shift
26

Identify the coordination complexes in which the central metal ion has $\mathrm{d}^4$ configuration.

(A) $\left[\mathrm{FeO}_4\right]^{2-}$

(B) $\quad\left[\mathrm{Mn}(\mathrm{CN})_6\right]^{3-}$

(C) $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$

(D) JEE Main 2025 (Online) 23rd January Evening Shift Chemistry - Coordination Compounds Question 27 English (E) $\left[\mathrm{NiF}_6\right]^{2-}$

Choose the correct answer from the options given below :

JEE Main 2025 (Online) 23rd January Evening Shift
27

$\mathrm{CrCl}_3 \cdot \mathrm{xNH}_3$ can exist as a complex. 0.1 molal aqueous solution of this complex shows a depression in freezing point of $0.558^{\circ} \mathrm{C}$. Assuming $100 \%$ ionisation of this complex and coordination number of Cr is 6 , the complex will be (Given $\mathrm{K}_{\mathrm{f}}=1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$ )

JEE Main 2025 (Online) 23rd January Morning Shift
28

The d-electronic configuration of an octahedral Co (II) complex having magnetic moment of 3.95 BM is:

JEE Main 2025 (Online) 23rd January Morning Shift
29

The complex that shows Facial - Meridional isomerism is :

JEE Main 2025 (Online) 23rd January Morning Shift
30

The correct order of the following complexes in terms of their crystal field stabilization energies is :

JEE Main 2025 (Online) 22nd January Evening Shift
31

Identify the homoleptic complex(es) that is/are low spin.

(A) $\left[\mathrm{Fe}(\mathrm{CN})_5 \mathrm{NO}\right]^{2-}$

(B) $\left[\mathrm{CoF}_6\right]^{3-}$

(C) $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{4-}$

(D) $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}$

(E) $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$

Choose the correct answer from the options given below :

JEE Main 2025 (Online) 22nd January Evening Shift
32

From the magnetic behaviour of $\left[\mathrm{NiCl}_4\right]^{2-}$ (paramagnetic) and $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$ (diamagnetic), choose the correct geometry and oxidation state.

JEE Main 2025 (Online) 22nd January Morning Shift
33
 

In which of the following complexes the CFSE, $\Delta_o$ will be equal to zero?

JEE Main 2025 (Online) 22nd January Morning Shift
34

Match List I with List II

LIST I LIST II
A. $$\mathrm{K}_2\left[\mathrm{Ni}(\mathrm{CN})_4\right]$$ I. $$sp^3$$
B. $$\left[\mathrm{Ni}(\mathrm{CO})_4\right]$$ II. $$sp^3d^2$$
C. $$\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right] \mathrm{Cl}_3$$ III. $$dsp^2$$
D. $$\mathrm{Na}_3\left[\mathrm{CoF}_6\right]$$ IV. $$d^2sp^3$$

Choose the correct answer from the options given below:

JEE Main 2024 (Online) 9th April Evening Shift
35

The coordination environment of $$\mathrm{Ca}^{2+}$$ ion in its complex with $$\mathrm{EDTA}^{4-}$$ is :

JEE Main 2024 (Online) 9th April Evening Shift
36

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A): The total number of geometrical isomers shown by $$[\mathrm{Co}(\mathrm{en})_2 \mathrm{Cl}_2]^{+}$$ complex ion is three.

Reason (R): $$[\mathrm{Co}(\mathrm{en})_2 \mathrm{Cl}_2]^{+}$$ complex ion has an octahedral geometry.

In the light of the above statements, choose the most appropriate answer from the options given below :

JEE Main 2024 (Online) 9th April Morning Shift
37

Match List I with List II

LIST I
(Complex ion)
LIST II
(Spin only magnetic moment in B.M.)
A. $$
\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_6\right]^{3+}
$$
I. 4.90
B. $$
\left[\mathrm{NiCl}_4\right]^{2-}
$$
II. 3.87
C. $$
\left[\mathrm{CoF}_6\right]^{3-}
$$
III. 0.0
D. $$
\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}
$$
IV. 2.83

Choose the correct answer from the options given below :

JEE Main 2024 (Online) 8th April Evening Shift
38

Number of Complexes with even number of electrons in $$\mathrm{t_{2 g}}$$ orbitals is -

$$\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+},\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+},\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+},\left[\mathrm{Cu}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+},\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$$

JEE Main 2024 (Online) 8th April Morning Shift
39

An octahedral complex with the formula $$\mathrm{CoCl}_3 \cdot \mathrm{nNH}_3$$ upon reaction with excess of $$\mathrm{AgNO}_3$$ solution gives 2 moles of $$\mathrm{AgCl}$$. Consider the oxidation state of $$\mathrm{Co}$$ in the complex is '$$x$$'. The value of "$$x+n$$" is __________.

JEE Main 2024 (Online) 8th April Morning Shift
40

Given below are two statements:

Statement I: $$\mathrm{N}\left(\mathrm{CH}_3\right)_3$$ and $$\mathrm{P}\left(\mathrm{CH}_3\right)_3$$ can act as ligands to form transition metal complexes.

Statement II: As N and P are from same group, the nature of bonding of $$\mathrm{N}\left(\mathrm{CH}_3\right)_3$$ and $$\mathrm{P}\left(\mathrm{CH}_3\right)_3$$ is always same with transition metals.

In the light of the above statements, choose the most appropriate answer from the options given below:

JEE Main 2024 (Online) 8th April Morning Shift
41

Match List I with List II

LIST I
(Compound)
LIST II
(Colour]
A. $$\mathrm{Fe}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]_3 \cdot \mathrm{xH_2O}$$ I. Violet
B. $$\left[\mathrm{Fe}(\mathrm{CN})_5 \mathrm{NOS}\right]^{4-}$$ II. Blood Red
C. $$[\mathrm{Fe}(\mathrm{SCN})]^{2+}$$ III. Prussian Blue
D. $$\left(\mathrm{NH}_4\right)_3 \mathrm{PO}_4\cdot12 \mathrm{MoO}_3$$ IV. Yellow

Choose the correct answer from the options given below:

JEE Main 2024 (Online) 8th April Morning Shift
42

Given below are two statements :

Statement I : $$\mathrm{PF}_5$$ and $$\mathrm{BrF}_5$$ both exhibit $$\mathrm{sp}^3 \mathrm{~d}$$ hybridisation.

Statement II : Both $$\mathrm{SF}_6$$ and $$[\mathrm{Co}(\mathrm{NH}_3)_6]^{3+}$$ exhibit $$\mathrm{sp}^3 \mathrm{~d}^2$$ hybridisation.

In the light of the above statements, choose the correct answer from the options given below :

JEE Main 2024 (Online) 6th April Evening Shift
43

Match List I with List II.

LIST I
Tetrahedral Complex
LIST II
Electronic configuration
A. $$
\mathrm{TiCl}_4
$$
I. $$
\mathrm{e}^2, \mathrm{t}_2^0
$$
B. $$
\left[\mathrm{FeO}_4\right]^{2-}
$$
II. $$
\mathrm{e^4, t_2^3}
$$
C. $$
\left[\mathrm{FeCl}_4\right]^{-}
$$
III. $$
\mathrm{e}^0, \mathrm{t}_2^0
$$
D. $$
\left[\mathrm{CoCl}_4\right]^{2-}
$$
IV. $$
\mathrm{e}^2, \mathrm{t}_2^3
$$

Choose the correct answer from the options given below :

JEE Main 2024 (Online) 6th April Evening Shift
44

The correct IUPAC name of $$[\mathrm{PtBr}_2(\mathrm{PMe}_3)_2]$$ is :

JEE Main 2024 (Online) 6th April Evening Shift
45

Consider the following complexes

(A) $$\left[\mathrm{CoCl}\left(\mathrm{NH}_3\right)_5\right]^{2+}$$, (B) $$\left[\mathrm{Co}(\mathrm{CN})_6\right]^{3-}$$, (C) $$ \left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5\left(\mathrm{H}_2 \mathrm{O}\right)\right]^{3+} $$, (D) $$\left[\mathrm{Cu}\left(\mathrm{H}_2 \mathrm{O}\right)_4\right]^{2+}$$

The correct order of A, B, C and D in terms of wavenumber of light absorbed is :

JEE Main 2024 (Online) 6th April Morning Shift
46

Match List I with List II

LIST I
(Hybridization)
LIST II
(Orientation in Shape)
A. sp$$^3$$ I. Trigonal bipyramidal
B. dsp$$^2$$ II. Octahedral
C. sp$$^3$$d III. Tetrahedral
D. sp$$^3$$d$$^2$$ IV. Square planar

Choose the correct answer from the options given below:

JEE Main 2024 (Online) 6th April Morning Shift
47

The number of complexes from the following with no electrons in the $$t_2$$ orbital is ______.

$$\mathrm{TiCl}_4,\left[\mathrm{MnO}_4\right]^{-},\left[\mathrm{FeO}_4\right]^{2-},\left[\mathrm{FeCl}_4\right]^{-},\left[\mathrm{CoCl}_4\right]^{2-}$$

JEE Main 2024 (Online) 5th April Evening Shift
48

The metal atom present in the complex MABXL (where A, B, X and L are unidentate ligands and $$\mathrm{M}$$ is metal) involves $$\mathrm{sp}^3$$ hybridization. The number of geometrical isomers exhibited by the complex is :

JEE Main 2024 (Online) 5th April Evening Shift
49

The correct order of ligands arranged in increasing field strength.

JEE Main 2024 (Online) 5th April Morning Shift
50

Which one of the following complexes will exhibit the least paramagnetic behaviour ? [Atomic number, $$\mathrm{Cr}=24, \mathrm{Mn}=25, \mathrm{Fe}=26, \mathrm{Co}=27$$]

JEE Main 2024 (Online) 5th April Morning Shift
51

If an iron (III) complex with the formula $$\left[\mathrm{Fe}\left(\mathrm{NH}_3\right)_x(\mathrm{CN})_y\right]^-$$ has no electron in its $$e_g$$ orbital, then the value of $$x+y$$ is

JEE Main 2024 (Online) 4th April Evening Shift
52

The number of unpaired d-electrons in $$\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$$ is ________.

JEE Main 2024 (Online) 4th April Evening Shift
53

A first row transition metal in its +2 oxidation state has a spin-only magnetic moment value of $$3.86 \mathrm{~BM}$$. The atomic number of the metal is

JEE Main 2024 (Online) 4th April Evening Shift
54

Number of complexes from the following with even number of unpaired "$$\mathrm{d}$$" electrons is ________ $$[\mathrm{V}(\mathrm{H}_2 \mathrm{O})_6]^{3+},[\mathrm{Cr}(\mathrm{H}_2 \mathrm{O})_6]^{2+},[\mathrm{Fe}(\mathrm{H}_2 \mathrm{O})_6]^{3+},[\mathrm{Ni}(\mathrm{H}_2 \mathrm{O})_6]^{3+},[\mathrm{Cu}(\mathrm{H}_2 \mathrm{O})_6]^{2+}$$ [Given atomic numbers: $$\mathrm{V}=23, \mathrm{Cr}=24, \mathrm{Fe}=26, \mathrm{Ni}=28 \mathrm{Cu}=29$$]

JEE Main 2024 (Online) 4th April Morning Shift
55

The correct sequence of ligands in the order of decreasing field strength is :

JEE Main 2024 (Online) 4th April Morning Shift
56
$\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}$ and $\left[\mathrm{CoF}_6\right]^{3-}$ are respectively known as :
JEE Main 2024 (Online) 1st February Evening Shift
57
Given below are two statements :

Statement (I) : Dimethyl glyoxime forms a six-membered covalent chelate when treated with $\mathrm{NiCl}_2$ solution in presence of $\mathrm{NH}_4 \mathrm{OH}$.

Statement (II) : Prussian blue precipitate contains iron both in $(+2)$ and $(+3)$ oxidation states.

In the light of the above statements, choose the most appropriate answer from the options given below :
JEE Main 2024 (Online) 1st February Evening Shift
58
Which of the following compounds show colour due to d-d transition?
JEE Main 2024 (Online) 1st February Evening Shift
59
Which of the following complex is homoleptic?
JEE Main 2024 (Online) 1st February Morning Shift
60
Given below are two statements :

Statement (I) : A solution of $\left[\mathrm{Ni}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$ is green in colour.

Statement (II) : A solution of $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$ is colourless.

In the light of the above statements, choose the most appropriate answer from the options given below :
JEE Main 2024 (Online) 1st February Morning Shift
61

Select the option with correct property -

JEE Main 2024 (Online) 31st January Evening Shift
62

Match List I with List II

List - I
(Complex ion)
List - II
(Electronic Configuration)
(A) $$\mathrm{[Cr(H_2O)_6]^{3+}}$$ (I) $$t_{2 g}{ }^2 e_g^0$$
(B) $$\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$$ (II) $$t_{2 g}{ }^3 e_g{ }^0$$
(C) $$\left[\mathrm{Ni}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$$ (III) $$t_{2 g}{ }^3 e_g{ }^2$$
(D) $$\left[\mathrm{V}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$$ (IV) $$t_{2 g}{ }^6 e_g^2$$

Choose the correct answer from the options given below:

JEE Main 2024 (Online) 31st January Evening Shift
63

The correct statements from following are:

A. The strength of anionic ligands can be explained by crystal field theory.

B. Valence bond theory does not give a quantitative interpretation of kinetic stability of coordination compounds.

C. The hybridization involved in formation of $$\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$$ complex is $$\mathrm{dsp}^2$$.

D. The number of possible isomer(s) of cis- $$\left[\mathrm{PtCl}_2(\mathrm{en})_2\right]^{2+}$$ is one

Choose the correct answer from the options given below:

JEE Main 2024 (Online) 31st January Morning Shift
64

The coordination geometry around the manganese in decacarbonyldimanganese $$(0)$$ is

JEE Main 2024 (Online) 30th January Evening Shift
65

Choose the correct statements from the following :

(A) Ethane-1, 2-diamine is a chelating ligand.

(B) Metallic aluminium is produced by electrolysis of aluminium oxide in presence of cryolite.

(C) Cyanide ion is used as ligand for leaching of silver.

(D) Phosphine act as a ligand in Wilkinson catalyst.

(E) The stability constants of $$\mathrm{Ca}^{2+}$$ and $$\mathrm{Mg}^{2+}$$ are similar with EDTA complexes.

Choose the correct answer from the options given below :

JEE Main 2024 (Online) 30th January Morning Shift
66

A reagent which gives brilliant red precipitate with Nickel ions in basic medium is

JEE Main 2024 (Online) 29th January Evening Shift
67

Match List I with List II

List - I
(Substances)
List - II
(Element Present)
(A) Ziegler catalyst (I) Rhodium
(B) Blood Pigment (II) Cobalt
(C) Wilkinson catalyst (III) Iron
(D) Vitamin $$\mathrm{B_{12}}$$ (IV) Titanium

Choose the correct answer from the options given below:

JEE Main 2024 (Online) 29th January Morning Shift
68

In which one of the following metal carbonyls, $$\mathrm{CO}$$ forms a bridge between metal atoms?

JEE Main 2024 (Online) 29th January Morning Shift
69

Identity the incorrect pair from the following :

JEE Main 2024 (Online) 27th January Evening Shift
70

Identify from the following species in which $$\mathrm{d}^2 \mathrm{sp}^3$$ hybridization is shown by central atom :

JEE Main 2024 (Online) 27th January Evening Shift
71

Consider the following complex ions

$$\begin{aligned} & \mathrm{P}=\left[\mathrm{FeF}_6\right]^{3-} \\ & \mathrm{Q}=\left[\mathrm{V}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+} \\ & \mathrm{R}=\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+} \end{aligned}$$

The correct order of the complex ions, according to their spin only magnetic moment values (in B.M.) is :

JEE Main 2024 (Online) 27th January Morning Shift
72

Yellow compound of lead chromate gets dissolved on treatment with hot $$\mathrm{NaOH}$$ solution. The product of lead formed is a :

JEE Main 2024 (Online) 27th January Morning Shift
73
The complex with highest magnitude of crystal field splitting energy $\left(\Delta_{0}\right)$ is :
JEE Main 2023 (Online) 15th April Morning Shift
74

The total number of stereoisomers for the complex $$\left[\mathrm{Cr}(o x)_{2} \mathrm{ClBr}\right]^{3-}$$ (where $$o x=$$ oxalate) is :

JEE Main 2023 (Online) 13th April Evening Shift
75

Which of the following complexes will exhibit maximum attraction to an applied magnetic field?

JEE Main 2023 (Online) 13th April Evening Shift
76

The mismatched combinations are

A. Chlorophyll - Co

B. Water hardness - EDTA

C. Photography $$-\left[\mathrm{Ag}(\mathrm{CN})_{2}\right]^{-}$$

D. Wilkinson catalyst $$-\left[\left(\mathrm{Ph}_{3} \mathrm{P}\right)_{3} \mathrm{RhCl}\right]$$

E. Chelating ligand - D-Penicillamine

Choose the correct answer from the options given below :

JEE Main 2023 (Online) 13th April Morning Shift
77

Match List I with List II

LIST I
Complex
LIST II
CFSE ($$\Delta_0$$)
A. $$\mathrm{[Cu(NH_3)_6]^{2+}}$$ I. $$-0.6$$
B. $$\mathrm{[Ti(H_2O)_6]^{3+}}$$ II. $$-2.0$$
C. $$\mathrm{[Fe(CN)_6]^{3-}}$$ III. $$-1.2$$
D. $$\mathrm{[NiF_6]^{4-}}$$ IV. $$-0.4$$

Choose the correct answer from the options given below:

JEE Main 2023 (Online) 12th April Morning Shift
78

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A : $$\left[\mathrm{CoCl}\left(\mathrm{NH}_{3}\right)_{5}\right]^{2+}$$ absorbs at lower wavelength of light with respect to $$\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5}\left(\mathrm{H}_{2} \mathrm{O}\right)\right]^{3+}$$

Reason R : It is because the wavelength of the light absorbed depends on the oxidation state of the metal ion.

In the light of the above statements, choose the correct answer from the options given below:

JEE Main 2023 (Online) 11th April Evening Shift
79

If $$\mathrm{Ni}^{2+}$$ is replaced by $$\mathrm{Pt}^{2+}$$ in the complex $$\left[\mathrm{NiCl}_{2} \mathrm{Br}_{2}\right]^{2-}$$, which of the following properties are expected to get changed ?

A. Geometry

B. Geometrical isomerism

C. Optical isomerism

D. Magnetic properties

JEE Main 2023 (Online) 11th April Evening Shift
80

Match List I with List II

LIST I
Complex
LIST II
Colour
A. $$Mg(N{H_4})P{O_4}$$ I. brown
B. $${K_3}[Co{(N{O_2})_6}]$$ II. white
C. $$MnO{(OH)_2}$$ III. yellow
D. $$F{e_4}{[Fe{(CN)_6}]_3}$$ IV. blue

Choose the correct answer from the options given below :

JEE Main 2023 (Online) 11th April Evening Shift
81

The magnetic moment is measured in Bohr Magneton (BM).

Spin only magnetic moment of $$\mathrm{Fe}$$ in $$\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}$$ and $$\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}$$ complexes respectively is :

JEE Main 2023 (Online) 11th April Evening Shift
82

The complex that dissolves in water is :

JEE Main 2023 (Online) 11th April Morning Shift
83

The set which does not have ambidentate ligand(s) is :

JEE Main 2023 (Online) 11th April Morning Shift
84

Which of the following complex has a possibility to exist as meridional isomer?

JEE Main 2023 (Online) 11th April Morning Shift
85

The correct order of the number of unpaired electrons in the given complexes is

A. $$\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}$$

B. $$\left[\mathrm{Fe} \mathrm{F}_{6}\right]^{3-}$$

C. $$\left[\mathrm{CoF}_{6}\right]^{3-}$$

D. $$\left.[\mathrm{Cr} \text { (oxalate})_{3}\right]^{3-}$$

E. $$\left[\mathrm{Ni}(\mathrm{CO})_{4}\right]$$

Choose the correct answer from the options given below:

JEE Main 2023 (Online) 10th April Evening Shift
86

Match List I with List II

List - I
Complex
List - II
Crystal Field splitting energy ($$\Delta_0$$)
A. $${[Ti{({H_2}O)_6}]^{2 + }}$$ I. $$-1.2$$
B. $${[V{({H_2}O)_6}]^{2 + }}$$ II. $$-0.6$$
C. $${[Mn{({H_2}O)_6}]^{3 + }}$$ III. 0
D. $${[Fe{({H_2}O)_6}]^{3 + }}$$ IV. $$-0.8$$

Choose the correct answer from the options given below:

JEE Main 2023 (Online) 10th April Evening Shift
87

The octahedral diamagnetic low spin complex among the following is :

JEE Main 2023 (Online) 10th April Morning Shift
88

Match List I with List II

LIST I
Coordination Complex
LIST II
Number of unpaired electrons
A. $$\left[\mathrm{Cr}(\mathrm{CN})_{6}\right]^{3-}$$ I. 0
B. $$\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}$$ II. 3
C. $$\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}$$ III. 2
D. $$\left[\mathrm{Ni}\left(\mathrm{NH}_{3}\right)_{6}\right]^{2+}$$ IV. 4

Choose the correct answer from the options given below:

JEE Main 2023 (Online) 8th April Evening Shift
89

Which of the following complex is octahedral, diamagnetic and the most stable?

JEE Main 2023 (Online) 8th April Morning Shift
90

The correct order of spin only magnetic moments for the following complex ions is

JEE Main 2023 (Online) 8th April Morning Shift
91

The IUPAC name of $$\mathrm{K}_{3}\left[\mathrm{Co}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{3}\right]$$ is:-

JEE Main 2023 (Online) 6th April Evening Shift
92

Given below are two statements, one is labelled as Assertion $$\mathbf{A}$$ and the other is labelled as Reason $$\mathbf{R}$$.

Assertion A: The spin only magnetic moment value for $$\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}$$ is $$1.74 \mathrm{BM}$$, whereas for $$\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}$$ is $$5.92 \mathrm{BM}$$.

Reason $$\mathbf{R}$$ : In both complexes, $$\mathrm{Fe}$$ is present in +3 oxidation state.

In the light of the above statements, choose the correct answer from the options given below:

JEE Main 2023 (Online) 6th April Morning Shift
93

The complex cation which has two isomers is :

JEE Main 2023 (Online) 1st February Evening Shift
94

Which of the following complex will show largest splitting of d-orbitals?

JEE Main 2023 (Online) 1st February Morning Shift
95

Which of the following are the example of double salt?

A. $$\mathrm{FeSO}_{4} \cdot\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4} \cdot 6 \mathrm{H}_{2} \mathrm{O}$$

B. $$\mathrm{CuSO}_{4}\cdot 4 \mathrm{NH}_{3} \cdot \mathrm{H}_{2} \mathrm{O}$$

C. $$\mathrm{K}_{2} \mathrm{SO}_{4} \cdot \mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3} \cdot 24 \mathrm{H}_{2} \mathrm{O}$$

D. $$\mathrm{Fe}(\mathrm{CN})_{2}\cdot4 \mathrm{KCN}$$

Choose the correct answer :

JEE Main 2023 (Online) 1st February Morning Shift
96

A solution of $$\mathrm{FeCl_3}$$ when treated with $$\mathrm{K_4[Fe(CN)_6]}$$ gives a prussium blue precipitate due to the formation of :

JEE Main 2023 (Online) 1st February Morning Shift
97

Cobalt chloride when dissolved in water forms pink colored complex $$\underline{\mathrm{X}}$$ which has octahedral geometry. This solution on treating with conc $$\mathrm{HCl}$$ forms deep blue complex, $$\underline{\mathrm{Y}}$$ which has a $$\underline{\mathrm{Z}}$$ geometry. $$\mathrm{X}, \mathrm{Y}$$ and $$\mathrm{Z}$$, respectively, are

JEE Main 2023 (Online) 31st January Morning Shift
98

Match List I with List II:

List I (Complexes) List II (Hybridisation)
A. $\left[\mathrm{Ni}(\mathrm{CO})_{4}\right]$ I. $\mathrm{sp}^{3}$
B. $\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+}$ II. dsp$^{2}$
C. $\left[\mathrm{Fe}\left(\mathrm{NH}_{3}\right)_{6}\right]^{2+}$ III. $\mathrm{sp}^{3}\mathrm{d}^{2}$
D. $\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}$ IV. $\mathrm{d}^{2} \mathrm{sp}^{3}$
JEE Main 2023 (Online) 30th January Evening Shift
99
The $\mathrm{Cl}-\mathrm{Co}-\mathrm{Cl}$ bond angle values in a fac- $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{3} \mathrm{Cl}_{3}\right]$ complex is/are :
JEE Main 2023 (Online) 30th January Evening Shift
100

To inhibit the growth of tumours, identify the compounds used from the following :

A. EDTA

B. Coordination Compounds of Pt

C. D - Penicillamine

D. Cis - Platin

Choose the correct answer from the option given below :

JEE Main 2023 (Online) 30th January Morning Shift
101

Which of the following is correct order of ligand field strength?

JEE Main 2023 (Online) 30th January Morning Shift
102

Correct order of spin only magnetic moment of the following complex ions is :

(Given At.no. Fe : 26, Co : 27)

JEE Main 2023 (Online) 29th January Evening Shift
103

Chiral complex from the following is :

Here en = ethylene diamine

JEE Main 2023 (Online) 29th January Morning Shift
104

Match List I with List II

List I
Coordination entity
List II
Wavelength of light absorbed in nm
A. $$\mathrm{[CoCl(NH_3)_5]^{2+}}$$ I. 310
B. $$\mathrm{[Co(NH_3)_6]^{3+}}$$ II. 475
C. $$\mathrm{[Co(CN)_6]^{3-}}$$ III. 535
D. $$\mathrm{[Cu(H_2O)_4]^{2+}}$$ IV. 600

Choose the correct answer from the options given below :

JEE Main 2023 (Online) 25th January Evening Shift
105

The hybridization and magnetic behaviour of cobalt ion in $$\mathrm{[Co(NH_3)_6]^{3+}}$$ complex, respectively is :

JEE Main 2023 (Online) 24th January Evening Shift
106

Which of the following cannot be explained by crystal field theory?

JEE Main 2023 (Online) 24th January Evening Shift
107

The primary and secondary valencies of cobalt respectively in $$\mathrm{[Co(NH_3)_5Cl]Cl_2}$$ are :

JEE Main 2023 (Online) 24th January Morning Shift
108

Octahedral complexes of copper(II) undergo structural distortion (Jahn-Teller). Which one of the given copper (II) complexes will show the maximum structural distortion? (en - ethylenediamine; $$\mathrm{H}_{2} \mathrm{~N}_{-} \mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{NH}_{2}$$)

JEE Main 2022 (Online) 29th July Evening Shift
109

Match List I with List II

List - I (Complex) List - II (Hybridization)
(A) $$Ni{(CO)_4}$$ (I) $$s{p^3}$$
(B) $${[Ni{(CN)_4}]^{2 - }}$$ (II) $$s{p^3}{d^2}$$
(C) $${[Co{(CN)_6}]^{3 - }}$$ (III) $${d^2}s{p^3}$$
(D) $${[Co{F_6}]^{3 - }}$$ (IV) $$ds{p^2}$$

Choose the correct answer from the options given below :

JEE Main 2022 (Online) 28th July Evening Shift
110

Low oxidation state of metals in their complexes are common when ligands :

JEE Main 2022 (Online) 27th July Evening Shift
111

$$\mathrm{Fe}^{3+}$$ cation gives a prussian blue precipitate on addition of potassium ferrocyanide solution due to the formation of :

JEE Main 2022 (Online) 27th July Evening Shift
112

The metal complex that is diamagnetic is (Atomic number: $$\mathrm{Fe}, 26 ; \mathrm{Cu}, 29)$$

JEE Main 2022 (Online) 26th July Evening Shift
113

The correct order of energy of absorption for the following metal complexes is :

A : [Ni(en)3]2+ , B : [Ni(NH3)6]2+ , C : [Ni(H2O)6]2+

JEE Main 2022 (Online) 25th July Evening Shift
114

Correct formula of the compound which gives a white precipitate with BaCl2 solution, but not with AgNO3 solution, is :

JEE Main 2022 (Online) 30th June Morning Shift
115

Given below are two statements.

$$\bullet$$ Statement I : In CuSO4 . 5H2O, Cu-O bonds are present.

$$\bullet$$ Statement II : In CuSO4 . 5H2O, ligands coordinating with Cu(II) ion are O-and S-based ligands.

In the light of the above statements, choose the correct answer from the options given below.

JEE Main 2022 (Online) 29th June Evening Shift
116

Given below are two statements :

Statement I : [Ni(CN)4]2$$-$$ is square planar and diamagnetic complex, with dsp2 hybridization for Ni but [Ni(CO)4] is tetrahedral, paramagnetic and with sp3-hybridication for Ni.

Statement II : [NiCl4]2$$-$$ and [Ni(CO)4] both have same d-electron configuration have same geometry and are paramagnetic.

In light the above statements, choose the correct answer from the options given below :

JEE Main 2022 (Online) 28th June Morning Shift
117

Arrange the following coordination compounds in the increasing order of magnetic moments. (Atomic numbers : Mn = 25; Fe = 26)

A. [FeF6]3$$-$$

B. [Fe(CN)6]3$$-$$

C. [MnCl6]3$$-$$ (high spin)

D. [Mn(CN)6]3$$-$$

Choose the correct answer from the options given below :

JEE Main 2022 (Online) 27th June Evening Shift
118

Which of the following will have maximum stabilization due to crystal field?

JEE Main 2022 (Online) 27th June Morning Shift
119

Which statement is not true with respect to nitrate ion test?

JEE Main 2022 (Online) 26th June Morning Shift
120

Transition metal complex with highest value of crystal field splitting ($$\Delta$$0) will be :

JEE Main 2022 (Online) 24th June Evening Shift
121

Match List - I with List - II :

List - I List -II
(A) $${[PtC{l_4}]^{2 - }}$$ (I) $$s{p^3}d$$
(B) $$Br{F_5}$$ (II) $${d^2}s{p^3}$$
(C) $$PC{l_5}$$ (III) $$ds{p^2}$$
(D) $${[Co{(N{H_3})_6}]^{3 + }}$$ (IV) $$s{p^3}{d^2}$$

Choose the most appropriate answer from the options given below :

JEE Main 2022 (Online) 24th June Morning Shift
122
The Crystal Field Stabilization Energy (CFSE) and magnetic moment (spin-only) of an octahedral aqua complex of a metal ion (Mz+) are $$-$$0.8 $$\Delta$$0 and 3.87 BM, respectively. Identify (Mz+) :
JEE Main 2021 (Online) 1st September Evening Shift
123
The potassium ferrocyanide solution gives a Prussian blue colour, when added to :
JEE Main 2021 (Online) 1st September Evening Shift
124
Spin only magnetic moment in BM of [Fe(CO)4(C2O4)]+ is :
JEE Main 2021 (Online) 31st August Evening Shift
125
The denticity of an organic ligand, biuret is :
JEE Main 2021 (Online) 31st August Morning Shift
126
Indicate the complex/complex ion which did not show any geometrical isomerism :
JEE Main 2021 (Online) 26th August Evening Shift
127
Arrange the following Cobalt complexes in the order of increasing Crystal Field Stabilization Energy (CFSE) value.

Complexes : $$\mathop {{{[Co{F_6}]}^{3 - }}}\limits_A ,\mathop {{{[Co{{({H_2}O)}_6}]}^{2 + }}}\limits_B ,\mathop {{{[Co{{(N{H_3})}_6}]}^{3 + }}}\limits_C and \mathop {{{[Co{{({en})}_3}]}^{3 + }}}\limits_D $$

Choose the correct option :
JEE Main 2021 (Online) 26th August Evening Shift
128
Given below are two statements :

Statement I : $${[Mn{(CN)_6}]^{3 - }}$$, $${[Fe{(CN)_6}]^{3 - }}$$ and $${[Co{({C_2}{O_4})_3}]^{3 - }}$$ are d2sp3 hybridised.

Statement II : $${[MnCl)_6}{]^{3 - }}$$ and $${[Fe{F_6}]^{3 - }}$$ are paramagnetic and have 4 and 5 unpaired electrons, respectively.

In the light of the above statements, choose the correct answer from the options given below :
JEE Main 2021 (Online) 27th July Evening Shift
129
The type of hybridisation and magnetic property of the complex [MnCl6]3$$-$$, respectively, are :
JEE Main 2021 (Online) 27th July Morning Shift
130
The number of geometrical isomers found in the metal
complexes [PtCl2(NH3)2], [Ni(CO)4], [Ru(H2O)3Cl3 and [CoCl2(NH3)4]+ respectively, are :
JEE Main 2021 (Online) 27th July Morning Shift
131
Which one of the following metal complexes is most stable?
JEE Main 2021 (Online) 25th July Evening Shift
132
Which one of the following species responds to an external magnetic field?
JEE Main 2021 (Online) 25th July Morning Shift
133
Spin only magnetic moment of an octahedral complex of Fe2+ in the presence of a strong field ligand in BM is :
JEE Main 2021 (Online) 20th July Evening Shift
134
Which one of the following species doesn't have a magnetic moment of 1.73 BM, (spin only value)?
JEE Main 2021 (Online) 20th July Evening Shift
135
According to the valence bond theory the hybridization of central metal atom is dsp2 for which one of the following compounds?
JEE Main 2021 (Online) 20th July Morning Shift
136
The correct order of intensity of colors of the compounds is :
JEE Main 2021 (Online) 20th July Morning Shift
137
The secondary valency and the number of hydrogen bonded water molecule(s) in CuSO4 . 5H2O, respectively, are :
JEE Main 2021 (Online) 18th March Evening Shift
138
The correct structures of trans-[NiBr2(PPh3)2] and meridonial-[Co(NH3)3(NO2)3], respectively, are
JEE Main 2021 (Online) 18th March Morning Shift
139
Match List - I with List - II :

List - I
List - II
(a) $$[Co{(N{H_3})_6}][Cr{(CN)_6}]$$ (i) Linkage isomerism
(b) $$[Co{(N{H_3})_3}{(N{O_2})_3}]$$ (ii) Solvate isomerism
(c) $$[Cr{({H_2}O)_6}C{l_3}$$ (iii) Co-ordination isomerism
(d) $$cis - {[CrC{l_2}{(ox)_2}]^{3 - }}$$ (iv) Optical isomerism


Choose the correct answer from the options given below :
JEE Main 2021 (Online) 17th March Evening Shift
140
In which of the following order the given complex ions are arranged correctly with respect to their decreasing spin only magnetic moment?

(i) [FeF6]3$$-$$

(ii) [Co(NH3)6]3+

(iii) [NiCl4]2$$-$$

(iv) [Cu(NH3)4]2+
JEE Main 2021 (Online) 25th February Evening Shift
141
The hybridization and magnetic nature of $${[Mn{(CN)_6}]^{4 - }}$$ and $${[Fe{(CN)_6}]^{3 - }}$$, respectively are :
JEE Main 2021 (Online) 25th February Morning Shift
142
The calculated magnetic moments (spin only value) for species $${[FeC{l_4}]^{2 - }}$$, $${[Co{({C_2}{O_4})_3}]^{3 - }}$$ and $$MnO_4^{2 - }$$ respectively are :
JEE Main 2021 (Online) 24th February Evening Shift
143
For a d4 metal ion in an octahedral field, the correct electronic configuration is :
JEE Main 2020 (Online) 6th September Evening Slot
144
The species that has a spin-only magnetic moment of 5.9 BM, is :
(Td = tetrahedral)
JEE Main 2020 (Online) 6th September Morning Slot
145
Consider the complex ions,
trans-[Co(en)2Cl2]+ (A) and
cis-[Co(en)2Cl2]+ (B).
The correct statement regarding them is :
JEE Main 2020 (Online) 5th September Evening Slot
146
The values of the crystal field stabilization energies for a high spin d6 metal ion in octahedral and tetrahedral fields, respectively, are :
JEE Main 2020 (Online) 5th September Morning Slot
147
The Crystal Field Stabilization Energy
(CFSE) of [CoF3(H2O)3] ($$\Delta $$0 < P) is :
JEE Main 2020 (Online) 4th September Evening Slot
148
The one that can exhibit highest paramagnetic behaviour among the following is :

gly = glycinato; bpy = 2, 2'-bipyridine
JEE Main 2020 (Online) 4th September Evening Slot
149
The molecule in which hybrid MOs involve only one d-orbital of the central atom is :
JEE Main 2020 (Online) 4th September Evening Slot
150
The pair in which both the species have the same magnetic moment (spin only) is :
JEE Main 2020 (Online) 4th September Morning Slot
151
The number of isomers possible for
[Pt(en)(NO2)2] is :
JEE Main 2020 (Online) 4th September Morning Slot
152
The d-electron configuration of [Ru(en)3 ]Cl2
and [Fe(H2O)6]Cl2 , respectively are :
JEE Main 2020 (Online) 3rd September Evening Slot
153
Complex A has a composition of H12O6Cl3Cr. If the complex on treatment with conc.H2SO4 loses 13.5% of its original mass, the correct molecular formula of A is :
[Given: atomic mass of Cr = 52 amu and Cl = 35 amu]
JEE Main 2020 (Online) 3rd September Evening Slot
154
The electronic spectrum of [Ti(H2O)6]3+ shows a single broad peak with a maximum at 20,300 cm-1 . The crystal field stabilization energy (CFSE) of the complex ion, in kJ mol-1, is :
JEE Main 2020 (Online) 3rd September Morning Slot
155
The complex that can show optical activity is :
JEE Main 2020 (Online) 3rd September Morning Slot
156
The one that is not expected to show isomerism is :
JEE Main 2020 (Online) 2nd September Evening Slot
157
Simplified absorption spectra of three complexes ((i), (ii) and (iii)) of Mn+ ion are provided below; their $$\lambda $$max values are marked as A, B and C respectively. The correct match between the complexes and their $$\lambda $$max values is JEE Main 2020 (Online) 2nd September Evening Slot Chemistry - Coordination Compounds Question 225 English
(i) [M(NCS)6](–6 + n)
(ii) [MF6](–6 + n)
(iii) [M(NH3)6]n+
JEE Main 2020 (Online) 2nd September Evening Slot
158
For octahedral Mn(II) and tetrahedral Ni(II) complexes, consider the following statements:

(I) both the complexes can be high spin.
(II) Ni(II) complex can very rarely be low spin.
(III) with strong field ligands, Mn(II) complexes can be low spin.
(IV)aqueous solution of Mn(II) ions is yellow in colour.

The correct statements are :
JEE Main 2020 (Online) 2nd September Morning Slot
159
Consider that a d6 metal ion (M2+) forms a complex with aqua ligands, and the spin only magnetic moment of the complex is 4.90 BM. The geometry and the crystal field stabilization energy of the complex is
JEE Main 2020 (Online) 2nd September Morning Slot
160
The correct order of the spin-only magnetic moments of the following complexes is :
(I) [Cr(H2O)6]Br2
(II) Na4[Fe(CN)6]
(III) Na3[Fe(C2O4)3] ($$\Delta $$0 $$>$$ P)
(IV) (Et4N)2[CoCl4]
JEE Main 2020 (Online) 9th January Evening Slot
161
The isomer(s) of [Co(NH3)4Cl2] that has/have a Cl–Co–Cl angle of 90°, is/are :
JEE Main 2020 (Online) 9th January Evening Slot
162
[Pd(F)(Cl)(Br)(I)]2– has n number of geometrical isomers. Then, the spin-only magnetic moment and crystal field stabilisation energy [CFSE] of [Fe(CN)6]n–6, respectively, are:
[Note : Ignore the pairing energy]
JEE Main 2020 (Online) 9th January Morning Slot
163
Complex X of composition Cr(H2O)6Cln has a spin only magnetic moment of 3.83 BM. It reacts with AgNO3 and shows geometrical isomerism. The IUPAC nomenclature of X is :
JEE Main 2020 (Online) 9th January Morning Slot
164
Among (a) – (d) the complexes that can display geometrical isomerism are :
(a) [Pt(NH3)3Cl]+
(b) [Pt(NH3)Cl5]
(c) [Pt(NH3)2Cl(NO2)]
(d) [Pt(NH3)4ClBr]2+
JEE Main 2020 (Online) 8th January Evening Slot
165
The correct order of the calculated spin-only magnetic moments of complexs (A) to (D) is:
(A) Ni(CO)4
(B) [Ni(H2O)6]Cl2
(C) Na2[Ni(CN)4]
(D) PdCl2(PPh3)2
JEE Main 2020 (Online) 8th January Evening Slot
166
The complex that can show fac- and mer-isomers is :
JEE Main 2020 (Online) 8th January Morning Slot
167
The number of possible optical isomers for the complexes MA2B2 with sp3 and dsp2 hydridized metal atom. respectively, is :
Note : A and B are unidentate netural and unidentate monoanionic ligands, respectively.
JEE Main 2020 (Online) 7th January Evening Slot
168
Among the statements(a)-(d) the incorrect ones are :
(a) Octahedral CO(III) complexes with strong fields ligands have very high magnetic moments.
(b) When $$\Delta $$0 < P, the d-electron configuration of Co(III) in an octahedral complex is $$t_{eg}^4e_g^2$$
(c) Wavelength of light absorbed by [Co(en)3]3+ is lower than that of [CoF6]3-
(d) If the $$\Delta $$0 for an octahedral complex of CO(III) is 18,000 cm-1, the $$\Delta $$t for its tetrahedral complex with the same ligand be 16,000 cm-1
JEE Main 2020 (Online) 7th January Evening Slot
169
The theory that can completely/properly explain the nature of bonding in [Ni(Co)4] is :
JEE Main 2020 (Online) 7th January Morning Slot
170
The IUPAC name of complex [Pt(NH3)2Cl(NH2CH3)]Cl is:
JEE Main 2020 (Online) 7th January Morning Slot
171
The coordination numbers of Co and Al in [Co(Cl)(en)2]Cl and K3[Al(C2O4)3], respectively, are : (en = ethane-1, 2-diamine)
JEE Main 2019 (Online) 12th April Evening Slot
172
The compound used in the treatment of lead poisoning is :
JEE Main 2019 (Online) 12th April Evening Slot
173
The complex ion that will lose its crystal field stabilization energy upon oxidation of its metal to +3 state is : JEE Main 2019 (Online) 12th April Morning Slot Chemistry - Coordination Compounds Question 244 English
JEE Main 2019 (Online) 12th April Morning Slot
174
Complete removal of both the axial ligands (along the z-axis) from an octahedral complex leads to which of the following splitting patterns? (relative orbital energies not on scale).
JEE Main 2019 (Online) 12th April Morning Slot
175
The crystal field stabilization energy (CFSE) of [Fe(H2O)6]Cl2 and K2[NiCl4] respectively, are :
JEE Main 2019 (Online) 10th April Evening Slot
176
The species that can have a trans-isomer is :
(en = ehane-1, 2-diamine, ox = oxalate)
JEE Main 2019 (Online) 10th April Morning Slot
177
Three complexes,
[CoCl(NH3)5] 2+(I),
[Co(NH3)5H2O]3+ (II) and
[Co(NH3)6] 3+(III)
absorb light in the visible region. The correct order of the wavelength of light absorbed by them is :
JEE Main 2019 (Online) 10th April Morning Slot
178
The maximum possible denticities of a ligand given below towards a common transition and inner-transition metal ion, respectively, are : JEE Main 2019 (Online) 9th April Evening Slot Chemistry - Coordination Compounds Question 249 English
JEE Main 2019 (Online) 9th April Evening Slot
179
The correct statements among I to III are :
(I) Valence bond theory cannot explain the color exhibited by transition metal complexes.
(II) Valence bond theory can predict quantitatively the magnetic properties of transtition metal complexes.
(III) Valence bond theory cannot distinguish ligands as weak and strong field ones.
JEE Main 2019 (Online) 9th April Evening Slot
180
The degenerate orbitals of [Cr(H2O)6]3+ are :
JEE Main 2019 (Online) 9th April Morning Slot
181
The one that will show optical activity is :
(en = ethane-1,2-diamine)
JEE Main 2019 (Online) 9th April Morning Slot
182
The calculated spin-only magnetic moments (BM) of the anionic and cationic species of [Fe(H2O)6]2 and [Fe(CN)6], respectively, are :
JEE Main 2019 (Online) 8th April Evening Slot
183
The compound that inhibits the growth of tumors is :
JEE Main 2019 (Online) 8th April Evening Slot
184
The correct order of the spin-only magnetic moment of metal ions in the following low-spin complexes, [V(CN)6]4–,[Fe(CN)6]4–, [Ru(NH3)6]3+, and [Cr(NH3)6]2+ , is :
JEE Main 2019 (Online) 8th April Morning Slot
185
The following ligand is : JEE Main 2019 (Online) 8th April Morning Slot Chemistry - Coordination Compounds Question 255 English
JEE Main 2019 (Online) 8th April Morning Slot
186
The magnetic moment of an octahedral homoleptic Mn(II) complex is 5.9 BM. The suitable ligand for this complex is -
JEE Main 2019 (Online) 12th January Evening Slot
187
The pair of metal ions that can give a spin only magnetic moment of 3.9 BM for the complex [M(H2O)6]Cl2, is -
JEE Main 2019 (Online) 12th January Morning Slot
188
The metal d-orbitals that are directly facing the ligands in K3[Co(CN)6] are -
JEE Main 2019 (Online) 12th January Morning Slot
189
Mn2(CO)10 is an organometallic compound due to the presence of -
JEE Main 2019 (Online) 12th January Morning Slot
190
The number of bridging CO ligand(s) and Co-Co bond(s) in Co2(CO)8, respectively are :
JEE Main 2019 (Online) 11th January Evening Slot
191
The coordination number of Th in K4[Th(C2O4)4(OH2)2] is :
(C2O$${_4^{2 - }}$$ = Oxalato)
JEE Main 2019 (Online) 11th January Evening Slot
192
Match the metals (column I) with the coordination compound(s)/enzyme(s) (column II)

(Column I) Metals
(Column II) Coordination
compounds(s) enzyme(s)
(A) Co (i) Wilkinson catalyst
(B) Zn (ii) Chlorophyl
(C) Rh (iii) Vitamin B12
(D) Mg (iv) Carbonic anhydrase
JEE Main 2019 (Online) 11th January Morning Slot
193
The difference in the number of unpaired electrons of a metal ion in its high spin and low-spin octahedral complexes is two. The metal ion is :
JEE Main 2019 (Online) 10th January Evening Slot
194
A reaction of cobalt (III) chloride and ethylenediamine in a 1 : 2 mole ratio generates two isomeric products A (violet coloured) and B (green coloured). A can show optical activity, but B is optically inactive. What type of isomers does A and B represcent?
JEE Main 2019 (Online) 10th January Evening Slot
195
The total number of isomers for a square planar complex
[M(F)(Cl)(SCN)(NO2)] is
JEE Main 2019 (Online) 10th January Morning Slot
196
The complex that has highest crystal field splitting energy ($$\Delta $$), is :
JEE Main 2019 (Online) 9th January Evening Slot
197
Homoleptic octahedral complexes of a metal ion 'M3+' with three monodenate ligands L1, L2 and L3 adsorb wavelenths in the region of green, blue and red respectively. The increasing order of the ligands strength is :
JEE Main 2019 (Online) 9th January Evening Slot
198
Two complexes [Cr(H2O)6]Cl3 (A) and [Cr(NH3)6]Cl3 (B) are violet and yellow coloured, respectively. The incorrect statement regarding them is :
JEE Main 2019 (Online) 9th January Morning Slot
199
In Wilkinson's catalyst, the hybridization of central metal ion and its shape are respectively :
JEE Main 2018 (Online) 16th April Morning Slot
200
Which of the following complexes will shows geometrical isomerism ?
JEE Main 2018 (Online) 16th April Morning Slot
201
Consider the following reaction and statements:
[Co(NH3)4Br2]+ + Br- $$\to$$ [Co(NH3)3Br3] + NH3
(I) Two isomers are produced if the reactant complex ion is a cis-isomer
(II) Two isomers are produced if the reactant complex ion is a trans-isomer
(III) Only one isomer is produced if the reactant complex ion is a trans-isomer
(IV) Only one isomer is produced if the reactant complex ion is a cis – isomer
The correct statements are
JEE Main 2018 (Offline)
202
The oxidation states of Cr in [Cr(H2O)6]Cl3, [Cr(C6H6)2] and K2[Cr(CN)2(O)2(O2)(NH3)] respectively are :
JEE Main 2018 (Offline)
203
The correct order of spin-only magnetic moments among the following is :
(Atomic number : Mn = 25, Co = 27, Ni = 28, Zn = 30)
JEE Main 2018 (Online) 15th April Evening Slot
204
The total number of possible isomers for square-planar [Pt(Cl)(NO2)(NO3)(SCN)]2- is :
JEE Main 2018 (Online) 15th April Evening Slot
205
The correct combination is :
JEE Main 2018 (Online) 15th April Morning Slot
206
[Co2(CO)8] displays :
JEE Main 2017 (Online) 9th April Morning Slot
207
On treatment of 100 mL of 0.1 M solution of CoCl3. 6H2O with excess AgNO3; 1.2 $$\times$$ 1022 ions are precipitated. The complex is :
JEE Main 2017 (Offline)
208
Which of the following is an example of homoleptic complex?
JEE Main 2016 (Online) 10th April Morning Slot
209
Which one of the following complexes will consume more equivalents of aqueous solution of Ag(NO3)?
JEE Main 2016 (Online) 9th April Morning Slot
210
Identify the correct trend given below : (Atomic No.=Ti : 22, Cr : 24 and Mo : 42)
JEE Main 2016 (Online) 9th April Morning Slot
211
The pair having the same magnetic moment is :
[At. No.: Cr = 24, Mn = 25, Fe = 26, Co = 27]
JEE Main 2016 (Offline)
212
Which one of the following complexes shows optical isomerism?
(en = ethylenediamine)
JEE Main 2016 (Offline)
213
The number of geometric isomers that can exist for square planar [Pt (Cl) (py) (NH3) (NH2OH)]+ is (py = pyridine) :
JEE Main 2015 (Offline)
214
Which of the following compounds is not colored yellow?
JEE Main 2015 (Offline)
215
The octahedral complex of a metal ion M3+ with four monodentate ligands L1, L2, L3 and L4 absorb wavelengths in the region of red, green, yellow and blue, respectively. The increasing order of ligand strength of the four ligands is :
JEE Main 2014 (Offline)
216
The equation which is balanced and represents the correct product(s) is :
JEE Main 2014 (Offline)
217
Which of the following complex species is not expected to exhibit optical isomerism?
JEE Main 2013 (Offline)
218
Which among the following will be named as dibromidobis (ethylene diamine) chromium(III) bromide?
AIEEE 2012
219
Which of the following facts about the complex [Cr (NH3)6 ]Cl3 is wrong?
AIEEE 2011
220
The magnetic moment (spin only) of [NiCl4]2− is
AIEEE 2011
221
Which one of the following has an optical isomer ?
(en = ethylenediamine)
AIEEE 2010
222
A solution containing 2.675g of CoCl3. 6NH3 (molar mass = 267.5 g mol–1) is passed through a cation exchanger. The chloride ions obtained in solution were treated with excess of AgNO3 to give 4.78 g of AgCl (molar mass = 143.5 g mol–1). The formula of the complex is : (At. Mass of Ag = 108 u)
AIEEE 2010
223
Which of the following pairs represents linkage isomers ?
AIEEE 2009
224
Which of the following has an optical isomer ?
AIEEE 2009
225
In which of the following octahedral complexes of Co (at. no. 27), will the magnitude of $$\Delta _o$$ be the highest?
AIEEE 2008
226
The coordination number and the oxidation state of the element ‘E’ in the complex [E(en)2(C2O4)]NO2 (where (en) is ethylene diamine) are, respectively,
AIEEE 2008
227
Which one of the following has a square planar geometry?
AIEEE 2007
228
The IUPAC name for the complex [Co(NO2)(NH3)5]Cl2 is
AIEEE 2006
229
How many EDTA (ethylenediaminetetraacetic acid) molecules are required to make an octahedral complex with a Ca2+ ion?
AIEEE 2006
230
In Fe(CO)5, the Fe – C bond possesses :
AIEEE 2006
231
Nickel (Z = 28) combines with a uninegative monodentate ligand X to form a paramagnetic complex [NiX4]2− . The number of unpaired electron(s) in the nickel and geometry of this complex ion are, respectively
AIEEE 2006
232
The IUPAC name of the coordination compound K3[Fe(CN)6] is
AIEEE 2005
233
The oxidation state of Cr in [Cr(NH3)4Cl2]+ is :
AIEEE 2005
234
Which of the following compounds shows optical isomerism?
AIEEE 2005
235
The value of the ‘spin only’ magnetic moment for one of the following configurations is 2.84 BM. The correct one is :
AIEEE 2005
236
Which one of the following cyano complexes would exhibit the lowest value of paramagnetic behaviour?
(At. No. Cr = 24, Mn = 25, Fe = 26, Co = 27)
AIEEE 2005
237
The coordination number of central metal atom in a complex is determined by :
AIEEE 2004
238
Among the properties (a) reducing (b) oxidising (c) complexing, the set of properties shown by CN ion towards metal species is :
AIEEE 2004
239
The correct order of magnetic moments (spin only values in B.M.) among is :
(Atomic numbers: Mn = 25; Fe = 26, Co =27)
AIEEE 2004
240
Which one the following has largest number of isomers? (R = alkyl group, en = ethylenediamine)
AIEEE 2004
241
Coordination compound have great importance in biological systems. In this context which of the following statements is incorrect?
AIEEE 2004
242
Which one of the following complexes in an outer orbital complex?
AIEEE 2004
243
Ammonia forms the complex ion [Cu(NH3)4]2+ with copper ions in alkaline solutions but not in acidic solutions. What is the reason for it?
AIEEE 2003
244
One mole of the complex compound Co(NH3)5Cl3, gives 3 moles of ions on dissolution in water. One mole of the same complex reacts with two moles of AgNO3 solution to yield two moles of AgCl (s). The structure of the complex is :
AIEEE 2003
245
In the coordination compound, K4[Ni(CN)4], the oxidation state of nickel is :
AIEEE 2003
246
The most stable ion is :
AIEEE 2002
247
CH3 - Mg - Br is an organometallic compound due to :
AIEEE 2002
248
The type isomerism present in nitropentammine chromium $$\left( {{\rm I}{\rm I}{\rm I}} \right)$$ chloride is :
AIEEE 2002

Numerical

1
The number of paramagnetic metal complex species among $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+},\left[\mathrm{Co}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]^{3-}$, $\left[\mathrm{MnCl}_6\right]^{3-},\left[\mathrm{Mn}(\mathrm{CN})_6\right]^{3-},\left[\mathrm{CoF}_6\right]^{3-},\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$ and $\left[\mathrm{FeF}_6\right]^{3-}$ with same number of unpaired electrons is __________.
JEE Main 2025 (Online) 7th April Evening Shift
2

The number of paramagnetic complexes among $\left[\mathrm{FeF}_6\right]^{3-},\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-},\left[\mathrm{Mn}(\mathrm{CN})_6\right]^{3-}$, $\left[\mathrm{Co}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]^{3-},\left[\mathrm{MnCl}_6\right]^{3-}$, and $\left[\mathrm{CoF}_6\right]^{3-}$, which involved $\mathrm{d}^2 \mathrm{sp}^3$ hybridization is _________.

JEE Main 2025 (Online) 7th April Morning Shift
3

A metal complex with a formula $\mathrm{MCl}_4 \cdot 3 \mathrm{NH}_3$ is involved in $\mathrm{sp}^3 \mathrm{~d}^2$ hybridisation. It upon reaction with excess of $\mathrm{AgNO}_3$ solution gives ' $x$ ' moles of AgCl . Consider ' $x$ ' is equal to the number of lone pairs of electron present in central atom of $\mathrm{BrF}_5$. Then the number of geometrical isomers exhibited by the complex is _________.

JEE Main 2025 (Online) 4th April Evening Shift
4

The number of optical isomers exhibited by the iron complex $(\mathrm{A})$ obtained from the following reaction is___________.

$$ \mathrm{FeCl}_3+\mathrm{KOH}+\mathrm{H}_2 \mathrm{C}_2 \mathrm{O}_4 \rightarrow \mathrm{~A} $$

JEE Main 2025 (Online) 3rd April Morning Shift
5

The spin-only magnetic moment value of $\mathrm{M}^{\mathrm{n}+}$ ion formed among $\mathrm{Ni}, \mathrm{Zn}, \mathrm{Mn}$ and Cu that has the least enthalpy of atomisation is_________ . (in nearest integer) Here n is equal to the number of diamagnetic complexes among $\mathrm{K}_2\left[\mathrm{NiCl}_4\right],\left[\mathrm{Zn}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right] \mathrm{Cl}_2$, $\mathrm{K}_3\left[\mathrm{Mn}(\mathrm{CN})_6\right]$ and $\left[\mathrm{Cu}\left(\mathrm{PPh}_3\right)_3 \mathrm{I}\right]$

JEE Main 2025 (Online) 2nd April Evening Shift
6

A transition metal (M) among $\mathrm{Mn}, \mathrm{Cr}, \mathrm{Co}$ and Fe has the highest standard electrode potential $\left(\mathrm{M}^{3+} / \mathrm{M}^{2+}\right)$. It forms a metal complex of the type $\left[\mathrm{M}(\mathrm{CN})_6\right]^{4-}$. The number of electrons present in the $\mathrm{e}_{\mathrm{g}}$ orbital of the complex is ___________.

JEE Main 2025 (Online) 2nd April Morning Shift
7

Consider the following low-spin complexes

$$ \mathrm{K}_3\left[\mathrm{Co}\left(\mathrm{NO}_2\right)_6\right], \mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right], \mathrm{K}_3\left[\mathrm{Fe}(\mathrm{CN})_6\right], \mathrm{Cu}_2\left[\mathrm{Fe}(\mathrm{CN})_6\right] \text { and } \mathrm{Zn}_2\left[\mathrm{Fe}(\mathrm{CN})_6\right] $$

The sum of the spin-only magnetic moment values of complexes having yellow colour is ________ B.M. (answer in nearest integer)

JEE Main 2025 (Online) 29th January Evening Shift
8
The spin only magnetic moment ( $\mu$ ) value (B.M.) of the compound with strongest oxidising power among $\mathrm{Mn}_2 \mathrm{O}_3, \mathrm{TiO}$ and VO is ____________ B.M. (Nearest integer).
JEE Main 2025 (Online) 28th January Evening Shift
9
Total number of molecules/species from following which will be paramagnetic is __________.

$\mathrm{O}_2, \mathrm{O}_2^{+}, \mathrm{O}_2^{-}, \mathrm{NO}, \mathrm{NO}_2, \mathrm{CO}, \mathrm{K}_2\left[\mathrm{NiCl}_4\right],\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right] \mathrm{Cl}_3, \mathrm{~K}_2\left[\mathrm{Ni}(\mathrm{CN})_4\right]$
JEE Main 2025 (Online) 28th January Evening Shift
10

The complex of $\mathrm{Ni}^{2+}$ ion and dimethyl glyoxime contains __________ number of Hydrogen (H) atoms.

JEE Main 2025 (Online) 22nd January Evening Shift
11

Consider the following test for a group-IV cation.

$$\mathrm{M}^{2+}+\mathrm{H}_2 \mathrm{S} \rightarrow \mathrm{A} \text { (Black precipitate)+ byproduct }$$

$$\mathrm{A}+\text { aqua regia } \rightarrow \mathrm{B}+\mathrm{NOCl}+\mathrm{S}+\mathrm{H}_2 \mathrm{O}$$

$$\mathrm{B}+\mathrm{KNO}_2+\mathrm{CH}_3 \mathrm{COOH} \rightarrow \mathrm{C}+\text { byproduct }$$

The spin-only magnetic moment value of the metal complex $$\mathrm{C}$$ is _________ $$\mathrm{BM}$$ (Nearest integer)

JEE Main 2024 (Online) 9th April Evening Shift
12

Number of ambidentate ligands among the following is _________.

$$\mathrm{NO}_2^{-}, \mathrm{SCN}^{-}, \mathrm{C}_2 \mathrm{O}_4^{2-}, \mathrm{NH}_3, \mathrm{CN}^{-}, \mathrm{SO}_4^{2-}, \mathrm{H}_2 \mathrm{O} \text {. }$$

JEE Main 2024 (Online) 9th April Morning Shift
13

Total number of unpaired electrons in the complex ions $$[\mathrm{Co}(\mathrm{NH}_3)_6]^{3+}$$ and $$[\mathrm{NiCl}_4]^{2-}$$ is ________.

JEE Main 2024 (Online) 8th April Evening Shift
14

The 'spin only' magnetic moment value of $$\mathrm{MO}_4{ }^{2-}$$ is ________ BM. (Where M is a metal having least metallic radii. among $$\mathrm{Sc}, \mathrm{Ti}, \mathrm{V}, \mathrm{Cr}, \mathrm{Mn}$$ and $$\mathrm{Zn}$$ ).

(Given atomic number: $$\mathrm{Sc}=21, \mathrm{Ti}=22, \mathrm{~V}=23, \mathrm{Cr}=24, \mathrm{Mn}=25$$ and $$\mathrm{Zn}=30$$)

JEE Main 2024 (Online) 8th April Morning Shift
15

The difference in the 'spin-only' magnetic moment values of $$\mathrm{KMnO}_4$$ and the manganese product formed during titration of $$\mathrm{KMnO}_4$$ against oxalic acid in acidic medium is ________ $$\mathrm{BM}$$. (nearest integer)

JEE Main 2024 (Online) 6th April Morning Shift
16

The spin-only magnetic moment value of the ion among $$\mathrm{Ti}^{2+}, \mathrm{V}^{2+}, \mathrm{Co}^{3+}$$ and $$\mathrm{Cr}^{2+}$$, that acts as strong oxidising agent in aqueous solution is _________ BM (Near integer).

(Given atomic numbers : $$\mathrm{Ti}: 22, \mathrm{~V}: 23, \mathrm{Cr}: 24, \mathrm{Co}: 27$$)

JEE Main 2024 (Online) 5th April Morning Shift
17

The 'Spin only' Magnetic moment for $$\left[\mathrm{Ni}\left(\mathrm{NH}_3\right)_6\right]^{2+}$$ is _________ $$\times 10^{-1} \mathrm{~BM}$$. (given $$=$$ Atomic number of $$\mathrm{Ni}: 28$$)

JEE Main 2024 (Online) 31st January Morning Shift
18

Number of complexes which show optical isomerism among the following is ________.

$$\text { cis- }\left[\mathrm{Cr}(\mathrm{ox})_2 \mathrm{Cl}_2\right]^{3-},\left[\mathrm{Co}(\text {en})_3\right]^{3+}, \text { cis- }\left[\mathrm{Pt}(\text {en})_2 \mathrm{Cl}_2\right]^{2+}, \text { cis- }\left[\mathrm{Co}(\text {en})_2 \mathrm{Cl}_2\right]^{+}, \text {trans- }\left[\mathrm{Pt}(\text {en})_2 \mathrm{Cl}_2\right]^{2+}, \text { trans- }\left[\mathrm{Cr}(\mathrm{ox})_2 \mathrm{Cl}_2\right]^{3-}$$

JEE Main 2024 (Online) 30th January Evening Shift
19

The Spin only magnetic moment value of square planar complex $$\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_2 \mathrm{Cl}\left(\mathrm{NH}_2 \mathrm{CH}_3\right)\right] \mathrm{Cl}$$ is _________ B.M. (Nearest integer)

(Given atomic number for $$\mathrm{Pt}=78$$)

JEE Main 2024 (Online) 27th January Evening Shift
20
The homoleptic and octahedral complex of $\mathrm{Co}^{2+}$ and $\mathrm{H}_{2} \mathrm{O}$ has ___________ unpaired electron(s) in the $t_{2\mathrm{g}}$ set of orbitals.
JEE Main 2023 (Online) 15th April Morning Shift
21

The ratio of spin-only magnetic moment values $$\mu_{\text {eff }}\left[\mathrm{Cr}(\mathrm{CN})_{6}\right]^{3-} / \mu_{\text {eff }}\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}$$ is _________.

JEE Main 2023 (Online) 11th April Morning Shift
22

For a metal ion, the calculated magnetic moment is $$4.90 ~\mathrm{BM}$$. This metal ion has ___________ number of unpaired electrons.

JEE Main 2023 (Online) 10th April Evening Shift
23

In potassium ferrocyanide, there are ________ pairs of electrons in the $$t_{2g}$$ set of orbitals.

JEE Main 2023 (Online) 10th April Morning Shift
24

The observed magnetic moment of the complex $$\left.\left[\operatorname{Mn}(\underline{N} C S)_{6}\right)\right]^{x^{-}}$$ is $$6.06 ~\mathrm{BM}$$. The numerical value of $$x$$ is __________.

JEE Main 2023 (Online) 8th April Evening Shift
25

Number of ambidentate ligands in a representative metal complex $$\left[\mathrm{M}(\mathrm{en})(\mathrm{SCN})_{4}\right]$$ is ___________.

[en = ethylenediamine]

JEE Main 2023 (Online) 6th April Morning Shift
26

The spin only magnetic moment of $$\left[\mathrm{Mn}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}$$ complexes is _________ B.M. (Nearest integer)

(Given : Atomic no. of Mn is 25)

JEE Main 2023 (Online) 1st February Evening Shift
27
If the CFSE of $\left[\mathrm{Ti}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}$ is $-96.0 \mathrm{~kJ} / \mathrm{mol}$, this complex will absorb maximum at wavelength ___________ $\mathrm{nm}$. (nearest integer)

Assume Planck's constant (h) $=6.4 \times 10^{-34} \mathrm{Js}$, Speed of light $(\mathrm{c})=3.0 \times 10^{8} \mathrm{~m} / \mathrm{s}$ and Avogadro's

Constant $\left(\mathrm{N}_{\mathrm{A}}\right)=6 \times 10^{23} / \mathrm{mol}$
JEE Main 2023 (Online) 31st January Evening Shift
28

The sum of bridging carbonyls in $$\mathrm{W(CO)_6}$$ and $$\mathrm{Mn_2(CO)_{10}}$$ is ____________.

JEE Main 2023 (Online) 29th January Morning Shift
29

Total number of moles of AgCl precipitated on addition of excess of AgNO$$_3$$ to one mole each of the following complexes $$\mathrm{[Co(NH_3)_4Cl_2]Cl,[Ni(H_2O)_6]Cl_2,[Pt(NH_3)_2Cl_2]}$$ and $$\mathrm{[Pd(NH_3)_4]Cl_2}$$ is ___________.

JEE Main 2023 (Online) 25th January Evening Shift
30

The number of paramagnetic species from the following is _____________.

$$\mathrm{{[Ni{(CN)_4}]^{2 - }},[Ni{(CO)_4}],{[NiC{l_4}]^{2 - }}}$$

$$\mathrm{{[Fe{(CN)_6}]^{4 - }},{[Cu{(N{H_3})_4}]^{2 + }}}$$

$$\mathrm{{[Fe{(CN)_6}]^{3 - }}\,and\,{[Fe{({H_2}O)_6}]^{2 + }}}$$

JEE Main 2023 (Online) 25th January Morning Shift
31

The d-electronic configuration of $$\mathrm{[CoCl_4]^{2-}}$$ in tetrahedral crystal field in $${e^mt_2^n}$$. Sum of "m" and "number of unpaired electrons" is ___________

JEE Main 2023 (Online) 24th January Morning Shift
32

Sum of oxidation state (magnitude) and coordination number of cobalt in $$\mathrm{Na}\left[\mathrm{Co}(\mathrm{bpy}) \mathrm{Cl}_{4}\right]$$ is _________.

JEE Main 2022 (Online) 29th July Evening Shift Chemistry - Coordination Compounds Question 139 English

JEE Main 2022 (Online) 29th July Evening Shift
33

$$\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}$$ should be an inner orbital complex. Ignoring the pairing energy, the value of crystal field stabilization energy for this complex is $$(-)$$ ____________ $$\Delta_{0}$$. (Nearest integer)

JEE Main 2022 (Online) 29th July Morning Shift
34

Total number of relatively more stable isomer(s) possible for octahedral complex $$\left[\mathrm{Cu}(\mathrm{en})_{2}(\mathrm{SCN})_{2}\right]$$ will be _________.

JEE Main 2022 (Online) 28th July Morning Shift
35

The conductivity of a solution of complex with formula $$\mathrm{CoCl}_{3}\left(\mathrm{NH}_{3}\right)_{4}$$ corresponds to 1 : 1 electrolyte, then the primary valency of central metal ion is __________.

JEE Main 2022 (Online) 27th July Morning Shift
36

The difference between spin only magnetic moment values of $$\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]\mathrm{Cl}_{2}$$ and $$\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right] \mathrm{Cl}_{3}$$ is ___________.

JEE Main 2022 (Online) 26th July Morning Shift
37

Consider the following metal complexes :

$$\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}$$

$$\left[\mathrm{CoCl}\left(\mathrm{NH}_{3}\right)_{5}\right]^{2+}$$

$$\left[\mathrm{Co}(\mathrm{CN})_{6}\right]^{3-}$$

$$\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5}\left(\mathrm{H}_{2} \mathrm{O}\right)\right]^{3+}$$

The spin-only magnetic moment value of the complex that absorbes light with shortest wavelength is _____________ B. M. (Nearest integer)

JEE Main 2022 (Online) 25th July Morning Shift
38

In the following brown complex, the oxidation state of iron is +_____________.

$${[Fe{({H_2}O)_6}]^{2 + }} + NO \to \mathop {{{[Fe{{({H_2}O)}_5}(NO)]}^{2 + }}}\limits_{\text{Brown complex}} + {H_2}O$$

JEE Main 2022 (Online) 30th June Morning Shift
39

Spin only magnetic moment ($$\mu$$s) of $${K_3}[Fe{(CN)_6}]$$ is ____________ B.M.

(Nearest integer)

JEE Main 2022 (Online) 30th June Morning Shift
40

$${[Fe{(CN)_6}]^{4 - }}$$

$${[Fe{(CN)_6}]^{3 - }}$$

$${[Ti{(CN)_6}]^{3 - }}$$

$${[Ni{(CN)_4}]^{2 - }}$$

$${[Co{(CN)_6}]^{3 - }}$$

Among the given complexes, number of paramagnetic complexes is ____________.

JEE Main 2022 (Online) 28th June Evening Shift
41

(a) CoCl3.4NH3,    (b) CoCl3.5NH3,      (c) CoCl3.6NH3    and    (d) CoCl(NO3)2.5NH3.

Number of complex(es) which will exist in cis-trans form is/are _______________.

JEE Main 2022 (Online) 28th June Evening Shift
42

Number of complexes which will exhibit synergic bonding amongst, $$[Cr{(CO)_6}]$$, $$[Mn{(CO)_5}]$$ and $$[M{n_2}{(CO)_{10}}]$$ is ___________.

JEE Main 2022 (Online) 28th June Morning Shift
43

Acidified potassium permanganate solution oxidises oxalic acid. The spin-only magnetic moment of the manganese product formed from the above reaction is ____________ B.M. (Nearest integer)

JEE Main 2022 (Online) 27th June Morning Shift
44

Reaction of [Co(H2O)6]2+ with excess ammonia and in the presence of oxygen results into a diamagnetic product. Number of electrons present in t2g-orbitals of the product is ___________.

JEE Main 2022 (Online) 26th June Evening Shift
45

The spin-only magnetic moment value of an octahedral complex among CoCl3.4NH3, NiCl2.6H2O and PtCl4.2HCl, which upon reaction with excess of AgNO3 gives 2 moles of AgCl is ___________ B.M. (Nearest integer)

JEE Main 2022 (Online) 26th June Morning Shift
46

Amongst FeCl3.3H2O, K3[Fe(CN)6] and [Co(NH3)6]Cl3, the spin-only magnetic moment value of the inner-orbital complex that absorbs light at shortest wavelength is ____________ B.M. [nearest integer]

JEE Main 2022 (Online) 25th June Evening Shift
47

If [Cu(H2O)4]2+ absorbs a light of wavelength 600 nm for d-d transition, then the value of octahedral crystal field splitting energy for [Cu(H2O)6]2+ will be ____________ $$\times$$ 10$$-$$21 J. [Nearest Integer]

(Given : h = 6.63 $$\times$$ 10$$-$$34 Js and c = 3.08 $$\times$$ 108 ms$$-$$1)

JEE Main 2022 (Online) 25th June Morning Shift
48

In the cobalt-carbonyl complex : [Co2(CO)8], number of Co-Co bonds is "X" and terminal CO ligands is "Y". X + Y = ___________.

JEE Main 2022 (Online) 24th June Morning Shift
49
The sum of oxidation states of two silver ions in [Ag(NH3)2] [Ag(CN)2] complex is _____________.
JEE Main 2021 (Online) 1st September Evening Shift
50
The number of optical isomers possible for [Cr(C2O4)3]3$$-$$ is ____________.
JEE Main 2021 (Online) 27th August Evening Shift
51
1 mol of an octahedral metal complex with formula MCl3 . 2L on reaction with excess of AgNO3 gives 1 mol of AgCl. The denticity of Ligand L is ____________. (Integer answer)
JEE Main 2021 (Online) 27th August Morning Shift
52
The overall stability constant of the complex ion [Cu(NH3)4]2+ is 2.1 $$\times$$ 1013. The overall dissociations constant is y $$\times$$ 10$$-$$14. Then y is __________. (Nearest integer)
JEE Main 2021 (Online) 26th August Evening Shift
53
The ratio of number of water molecules in Mohr's salt and potash alum is ____________ $$\times$$ 10$$-$$1. (Integer answer)
JEE Main 2021 (Online) 26th August Morning Shift
54
3 moles of metal complex with formula Co(en)2Cl3 gives 3 moles of silver chloride on treatment with excess of silver nitrate. The secondary valency of Co in the complex is ___________.

(Round off to the nearest integer)
JEE Main 2021 (Online) 27th July Evening Shift
55
The number of geometrical isomers possible in triamminetrinitrocobalt (III) is X and in trioxalatochromate (III) is Y. Then the value of X + Y is _______________.
JEE Main 2021 (Online) 27th July Morning Shift
56
Three moles of AgCl get precipitated when one mole of an octahedral co-ordination compound with empirical formula CrCl3.3NH3.3H2O reacts with excess of silver nitrate. The number of chloride ions satisfying the secondary valency of the metal ion is ______________.
JEE Main 2021 (Online) 25th July Morning Shift
57
The total number of unpaired electrons present in [Co(NH3)6]Cl2 and [Co(NH3)6]Cl3 is :
JEE Main 2021 (Online) 22th July Evening Shift
58
An aqueous solution of NiCl2 was heated with excess sodium cyanide in presence of strong oxidizing agent to form [Ni(CN)6]2$$-$$. The total change in number of unpaired electrons on metal centre is _______________.
JEE Main 2021 (Online) 20th July Evening Shift
59
The spin-only magnetic moment value for the complex [Co(CN)6]4$$-$$ is __________ BM.

[At. no. of Co = 27]
JEE Main 2021 (Online) 20th July Morning Shift
60
The total number of unpaired electrons present in the complex K3[Cr(oxalate)3] is _____________.
JEE Main 2021 (Online) 18th March Morning Shift
61
On complete reaction of FeCl3 with oxalic acid in aqueous solution containing KOH, resulted in the formation of product A. The secondary valency of Fe in the product A is __________. (Round off to the Nearest Integer).
JEE Main 2021 (Online) 17th March Evening Shift
62
[Ti(H2O)6]3+ absorbs light of wavelength 498 nm during a d $$-$$ d transition. The octahedral splitting energy for the above complex is ____________ $$\times$$ 10$$-$$19 J. (Round off to the Nearest Integer). h = 6.626 $$\times$$ 10$$-$$34 Js; c = 3 $$\times$$ 108 ms$$-$$1
JEE Main 2021 (Online) 16th March Evening Shift
63
The equivalents of ethylene diamine required to replace the neutral ligands from the coordination sphere of the trans-complex of CoCl3 . 4NH3 is _________. (Round off to the Nearest Integer).
JEE Main 2021 (Online) 16th March Morning Shift
64
The number of stereoisomers possible for [Co(ox)2(Br)(NH3)]2$$-$$ is ___________. [ox = oxalate]
JEE Main 2021 (Online) 26th February Evening Shift
65
Number of bridging CO ligands in [Mn2(CO)10] is __________.
JEE Main 2021 (Online) 26th February Morning Shift
66
The spin only magnetic moment of a divalent ion in aqueous solution (atomic number 29) is _________ BM.
JEE Main 2021 (Online) 25th February Evening Shift
67
Considering that $$\Delta $$0 > P, the magnetic moment
(in BM) of [Ru(H2O)6]2+ would be _________.
JEE Main 2020 (Online) 5th September Evening Slot
68
The total number of coordination sites
in ethylenediaminetetraacetate (EDTA4–) is _____.
JEE Main 2020 (Online) 5th September Morning Slot
69
The oxidation states of iron atoms in compounds (A), (B) and (C), respectively, are x, y and z. The sum of x, y and z is ________.

Na4[Fe(CN)5(NOS)]
       (A)

Na4[FeO4]
       (B)

[Fe2(CO)9]
       (C)
JEE Main 2020 (Online) 2nd September Morning Slot
70
Complexes (ML5) of metals Ni and Fe have ideal square pyramidal and trigonal bipyramidal grometries, respectively. The sum of the 90°, 120° and 180° L-M-L angles in the two complexes is ________.
JEE Main 2020 (Online) 8th January Evening Slot
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