Coordination Compounds · Chemistry · COMEDK

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MCQ (Single Correct Answer)

1

Which one of the following complex-isomerism pair matches correctly?

COMEDK 2026 Afternoon Shift
2

Identify the complex which exhibits all 3 characteristics; paramagnetic; high spin configuration; octahedral geometry

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3

$$ \text { Match the Coordination compounds in Column I with the type of stereoisomerism given in Column II exhibited by them. } $$

$$
\text { Column I }
$$
$$
\text { Column I }
$$
A $$
\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_2 \mathrm{Cl}_2\right]
$$
P fac-mer
B $$
\mathrm{Ni}\left[\left(\mathrm{NH}_3\right)_2 \mathrm{Cl}_2\right]
$$
Q cis -trans
C $$
\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_3\left(\mathrm{NO}_2\right)_3\right]
$$
R only cis isomer shows optical isomerism
D $$
\left[\mathrm{Pt} \mathrm{Cl}_2(\mathrm{en})_2\right]^{2+}
$$
S does not exhibit isomerism.
COMEDK 2026 Morning Shift
4

The Crystal Field Stabilisation energy of (i) $\left[\mathrm{CoF}_6\right]^{3-}$ and (ii) $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$ are ⋯and ⋯⋯ respectively.

COMEDK 2026 Morning Shift
5

Arrange the complex ions in the increasing order of their magnetic moments

A. $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$
B. $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{4-}$
C. $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$
D. $\left[\mathrm{FeF}_6\right]^{3-}$

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6
Which of the following compounds has electrons symmetrically distributed in both $\mathrm{t}_{2 \mathrm{~g}}$ and $\mathrm{e}_{\mathrm{g}}$ orbitals?
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7

Which of the coordination compounds [(i) to (v)] are used for the following processes :

A: Electroplating

B: Removal of excess copper from human body

C: Estimation of hardness of water

(i) DMG (ii) $\mathrm{Na}_2 \mathrm{EDTA}$ (iii) Cis-platin (iv) D-penicillamine (v) $\mathrm{K}\left[\mathrm{Au}(\mathrm{CN})_2\right]$

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8

Which one of the following structures in Column I does not have the correct IUPAC name as given in Column II.

S.No. Structure IUPAC name
A. $\left[\mathrm{CoBr}_2(\mathrm{en})_2\right] \mathrm{Cl}$ P. Dibromidodi-( ethan-1, 2 - diamine)cobalt (III) chloride
B. $\mathrm{Na}\left[\mathrm{PtBrCl}\left(\mathrm{NO}_2\right)\left(\mathrm{NH}_3\right)\right]$ Q. Sodium amminebromidochloridonitrito- N - palatinate(II)
C. $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_2\left(\mathrm{NH}_3\right)_4 \mathrm{Cl}\right] \mathrm{SO}_4$ R. Tetraamminediaquachloridochromium (III) sulphate.
D. $\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_4\right]\left[\mathrm{PtCl}_4\right]$ S. Tetraammineplatinum (II) tetrachloridoplatinate (II)

COMEDK 2025 Afternoon Shift
9
A transition metal M forms 4 homoleptic octahedral coordination compounds, $\mathrm{A}, \mathrm{B}, \mathrm{C}$ and D of the type $\left[\mathrm{MX}_6\right]^{z-}$ with monodentate ligands a, b, c and d respectively. These compounds absorb red. blue. yellow and blue-green light respectively. Which one of the options shows the correct order of decreasing ligand strength?
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10
Choose the coordination compound which does not exhibit Optical activity.
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11
The correct order of spin only magnetic moments among the following is: [Given: Atomic numbers: $\mathrm{Mn}=25, \mathrm{Fe}=26, \mathrm{Co}=27$ ]
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12
An aqueous solution of $\mathrm{CrCl}_3 .6 \mathrm{H}_2 \mathrm{O}$ (Molar mass $=266.5 \mathrm{~g} / \mathrm{mol}$ ) containing 2.665 g of the solute after processing, when treated with excess of $\mathrm{AgNO}_3$ gave 2.87 g of AgCl (Molar mass of $\mathrm{AgCl}=143.5 \mathrm{~g} / \mathrm{mol}$ ) Choose the correct formula of the compound which give these results.
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13
Which one of the following coordination compounds will exhibit both geometrical and optical isomerism?
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14

Arrange the following compounds in the decreasing order of the molar conductivities of their aqueous solutions.

A B C D
$\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}\right] \mathrm{Cl}_2$ $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_3 \mathrm{Cl}_3\right]$ $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_4 \mathrm{Cl}_2\right] \mathrm{Cl}$ $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right] \mathrm{Cl}_3$

COMEDK 2025 Morning Shift
15

Match the coordination compounds in Column I having the given type of hybridisation of $\mathrm{M}^{\mathrm{n}+}$ ion and magnetic moment as given in Column II.

Coordination compounds Hybridisation & Magnetic nature
A. $\mathrm{Ni}(\mathrm{CO})_4$ P. $\mathrm{sp}^3, \quad \mu=5.92 \mathrm{BM}$
B. $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$ Q. $\mathrm{sp}^3, \quad \mu=2.84 \mathrm{BM}$
C. $\left[\mathrm{Ni}(\mathrm{Cl})_4\right]^{2-}$ R. $\mathrm{sp}^3, \quad \mu=0$
D. $\left[\mathrm{MnBr}_4\right]^{2-}$ S. $\mathrm{dsp}^2, \quad \mu=0$

COMEDK 2025 Morning Shift
16

Which of the following 2 compounds exhibit both Geometrical and Structural isomerism?

$$\begin{aligned} & \mathrm{A}=\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_4 \mathrm{Cl}_2\right] \mathrm{NO}_2 \\ & \mathrm{~B}=\left[\mathrm{Co}\left(\mathrm{NH}_3\right) \mathrm{Br}\right] \mathrm{SO}_4 \\ & \mathrm{C}=\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_3\left(\mathrm{NO}_2\right)_3\right] \\ & \mathrm{D}=\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right] \mathrm{Cl}_3 \end{aligned}$$

COMEDK 2024 Evening Shift
17

Based on Valence Bond Theory, match the complexes listed in Column I with the number of unpaired electrons on the central metal ion, given in Column II

No. Complex ions No. Number of unpaired electrons
(A) $$
\left[\mathrm{Fe} \mathrm{F}_6\right]^{3-}
$$
(P) 0
(B) $$
\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{4-}
$$
(P) 1
(C) $$
\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}
$$
(R) 5
(D) $$
\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}
$$
(S) 4

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18

Given below are 4 statements. Two of these are correct statements. Identify them.

A. $$\mathrm{Co}^{2+}$$ is easily oxidised to $$\mathrm{Co}^{3+}$$ in the presence of a strong ligand like $$\mathrm{CN}^{-}$$

B. $$[\mathrm{Fe}(\mathrm{CN})_6]^{4-}$$ is an octahedral complex ion which is paramagnetic in nature.

C. Removal of $$\mathrm{H}_2 \mathrm{O}$$ molecules from $$[\mathrm{Ti}(\mathrm{H}_2 \mathrm{O})_6] \mathrm{Cl}_3$$ on strong heating converts it to a colourless compound.

D. Crystal Field splitting in Octahedral and Tetrahedral complexes is given by the equation $$\Delta_0=4 / 9 \Delta_t$$

COMEDK 2024 Evening Shift
19

Based on Crystal Field theory, match the Complex ions listed in Column I with the electronic configuration in the d orbitals of the central metal ion listed in Column II.

No. Complexion No. d orbital configuration of central metal ion.
(A) $$
\left[M n(C N)_6\right]^{4-}
$$
(P) $$
e_g^2 t_{2 g}^3
$$
(B) $$
\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}
$$
(Q) $$
t_{2 g}^4 e_g^2
$$
(C) $$
\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}
$$
(R) $$
t_{2 g}^5
$$
(D) $$
\left[\mathrm{MnCl}_4\right]^{2-}
$$
(S) $$
t_{2 g}^5 e_g^2
$$

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20

On the basis of crystal field theory, electronic configuration of a low spin $$\mathrm{d}^4$$ complex is:

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21

The molar conductivity of the complex $$\mathrm{CoCl}_3 \cdot 4 \mathrm{NH}_3 \cdot 2 \mathrm{H}_2 \mathrm{O}$$ is found to be the same as that of a $$1: 3$$ electrolyte. The structural formula of the compound is :

COMEDK 2024 Afternoon Shift
22

The type of hybridisation and the spin only magnetic moment for the complex $$[\mathrm{Ni}(\mathrm{CO})_4]$$ are respectively:

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23

A d - block metal $$\mathrm{X}(\mathrm{Z}=26)$$ forms a compound $$[\mathrm{X}(\mathrm{CN})_2(\mathrm{CO})_4]^{+}$$. Calculate its spin magnetic moment value.

COMEDK 2024 Morning Shift
24

A Coordination compound is represented by the formula $$[\mathrm{CoBr}_3(e n) x]$$. This compound required one mole of $$\mathrm{AgNO}_3$$ to form a pale yellow precipitate of $$\mathrm{AgBr}$$. What is the value of $$\mathrm{x}$$ in the compound?

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25

Choose the incorrect statement from the following.

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26

Which among the following is diamagnetic?

COMEDK 2023 Morning Shift
27

The complex $$\left[\mathrm{PtCl}_2(\mathrm{en})_2\right]^{2+}$$ ion shows

COMEDK 2023 Morning Shift
28

The blue colouration obtained from the Lassaigne's test of nitrogen is due to the formation of

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29

Aqueous $$\mathrm{CuSO}_4$$ changes its colour from sky blue to deep blue on addition of $$\mathrm{NH}_3$$ because

COMEDK 2023 Morning Shift
30

Which of the following complex show optical isomerism?

(i) $$c i s-\left[\mathrm{COCl}(\mathrm{en})_2\left(\mathrm{NH}_3\right)\right]^{2+}$$

(ii) $$cis-\left[\mathrm{CrCl}_2(\mathrm{ox})_2\right]^{3-}$$

(iii) $$cis-[ \left.\mathrm{CO}(\mathrm{en})_2 \mathrm{Cl}_2\right] \mathrm{Cl}$$

(iv) $$cis- \left[\mathrm{CO}\left(\mathrm{NH}_3\right)_4 \mathrm{Cl}_2\right]^{+}$$

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31

Mohr's salt has the formula

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32

Identify the correct IUPAC name of $$[\mathrm{CoCl}_2(\mathrm{NO}_2)(\mathrm{NH}_3)_3]$$

COMEDK 2023 Evening Shift
33

Match the Coordination compounds given in Column I with their characteristic features listed in Column II.

S.No. Coordination compounds S.No. Characteristic features
W $$
\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}\right] \mathrm{Cl}_3
$$
P $$
\text { Oxidation state }=+3 \text { Configuration }=\mathrm{d}^5 \quad \mu=5.92 \mathrm{BM}
$$
X $$
\mathrm{K}_4\left[\mathrm{Mn}(\mathrm{CN})_6\right.
$$
Q $$
\text { Oxidation state }=+3 \text { Configuration }=\mathrm{d}^3 \quad \mu=3.87 \mathrm{BM}
$$
Y $$
\left[\mathrm{CrCl}_3(\mathrm{py})_3\right]
$$
R $$
\text { Oxidation state }=+3 \text { Configuration }=d^6 \quad \mu=0 \mathrm{BM}
$$
Z $$
\mathrm{Cs}\left[\mathrm{FeCl}_4\right]
$$
S $$
\text { Oxidation state }=+2 \text { Configuration }=\mathrm{d}^5 \quad \mu=1.732 \mathrm{BM}
$$

COMEDK 2023 Evening Shift
34

Which one of the following is an incorrect statement pertaining to the properties of Coordination compounds?

COMEDK 2023 Evening Shift
35

Which one of the following Coordination entities exhibits Facial and Meridional isomerism?

COMEDK 2023 Evening Shift
36

The complex which does not show optical isomerism is

COMEDK 2022
37

The oxidation state of nickel in [Ni(CO$$_4$$)] is

COMEDK 2022
38

Which type of ligand is EDTA?

COMEDK 2021
39

The correct IUPAC name of the coordination compound K$$_3$$[Fe(CN)$$_5$$NO] is

COMEDK 2021
40

IUPAC name of Na$$_3$$[Co(NO$$_2$$)$$_6$$] is

COMEDK 2020
41

The number of unidentate ligands in the complex ion is called

COMEDK 2020
42

The oxidation state of iron in K$$_4$$[Fe(CN)$$_6$$] is,

COMEDK 2020
43

Which complex cannot ionise in solution?

COMEDK 2020