MCQ (Single Correct Answer)

1

The correct option with order of melting points of the pairs (Mn, Fe), (Tc, Ru) and (Re, Os) is :

JEE Main 2025 (Online) 29th January Morning Shift
2
The amphoteric oxide among $\mathrm{V}_2 \mathrm{O}_3, \mathrm{~V}_2 \mathrm{O}_4$ and $\mathrm{V}_2 \mathrm{O}_5$, upon reaction with alkali leads to formation of an oxide anion. The oxidation state of V in the oxide anion is :
JEE Main 2025 (Online) 28th January Evening Shift
3

The metal ion whose electronic configuration is not affected by the nature of the ligand and which gives a violet colour in non-luminous flame under hot condition in borax bead test is

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4

Match List - I with List - II.

List - I
(Transition metal ion)
List - II
(Spin only magnetic moment (B.M.))
(A) $\mathrm{Ti}^{3+}$ (I) 3.87
(B) $\mathrm{V}^{2+}$ (II) 0.00
(C) $\mathrm{Ni}^{2+}$ (III) 1.73
(D) $\mathrm{Sc}^{3+}$ (IV) 2.84

Choose the correct answer from the options given below :

JEE Main 2025 (Online) 24th January Evening Shift
5

Preparation of potassium permanganate from $\mathrm{MnO}_2$ involves two step process in which the 1st step is a reaction with KOH and $\mathrm{KNO}_3$ to produce

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6

Which of the following ions is the strongest oxidizing agent? (Atomic Number of $\mathrm{Ce}=58, \mathrm{Eu}=63, \mathrm{~Tb}=65, \mathrm{Lu}=71$)

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7

Match List - I with List - II

List - I List - II
(A) Bronze (I) Cu, Ni
(B) Brass (II) Fe, Cr, Ni, C
(C) UK silver coin (III) Cu, Zn
(D) Stainless steel (IV) Cu, Sn

Choose the correct answer from the options given below :

JEE Main 2025 (Online) 23rd January Evening Shift
8

Consider the following reactions

$$\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7 \xrightarrow[-\mathrm{H}_2 \mathrm{O}]{\mathrm{KOH}}[\mathrm{~A}] \xrightarrow[-\mathrm{H}_2 \mathrm{O}]{\mathrm{H}_2 \mathrm{SO}_4}[\mathrm{~B}]+\mathrm{K}_2 \mathrm{SO}_4$$

The products $[A]$ and $[B]$, respectively are :

JEE Main 2025 (Online) 23rd January Evening Shift
9

The correct set of ions (aqueous solution) with same colour from the following is:

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10

Lanthanoid ions with $4 \mathrm{f}^7$ configuration are :

(A) $\mathrm{Eu}^{2+}$

(B) $\mathrm{Gd}^{3+}$

(C) $\mathrm{Eu}^{3+}$

(D) $\mathrm{Tb}^{3+}$

(E) $ \mathrm{Sm}^{2+}$

Choose the correct answer from the options given below :

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

The electronic configuration of Einsteinium is :

(Given atomic number of Einsteinium $$=99$$)

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12

Give below are two statements :

Statement I : The higher oxidation states are more stable down the group among transition elements unlike p-block elements.

Statement II : Copper can not liberate hydrogen from weak acids.

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

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13

The electronic configuration of $$\mathrm{Cu}(\mathrm{II})$$ is $$3 \mathrm{~d}^9$$ whereas that of $$\mathrm{Cu}(\mathrm{I})$$ is $$3 \mathrm{~d}^{10}$$. Which of the following is correct?

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14

Iron (III) catalyses the reaction between iodide and persulphate ions, in which

A. $$\mathrm{Fe}^{3+}$$ oxidises the iodide ion

B. $$\mathrm{Fe}^{3+}$$ oxidises the persulphate ion

C. $$\mathrm{Fe}^{2+}$$ reduces the iodide ion

D. $$\mathrm{Fe}^{2+}$$ reduces the persulphate ion

Choose the most appropriate answer from the options given below:

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

Arrange the following elements in the increasing order of number of unpaired electrons in it.

(A) $$\mathrm{Sc}$$

(B) $$\mathrm{Cr}$$

(C) $$\mathrm{V}$$

(D) $$\mathrm{Ti}$$

(E) $$\mathrm{Mn}$$

Choose the correct answer from the options given below :

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

The number of element from the following that do not belong to lanthanoids is $$\mathrm{Eu}, \mathrm{Cm}, \mathrm{Er}, \mathrm{Tb}, \mathrm{Yb}$$ and $$\mathrm{Lu}$$

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17

While preparing crystals of Mohr's salt, dil $$\mathrm{H}_2 \mathrm{SO}_4$$ is added to a mixture of ferrous sulphate and ammonium sulphate, before dissolving this mixture in water, dil $$\mathrm{H_2SO_4}$$ is added here to :

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18

The number of ions from the following that have the ability to liberate hydrogen from a dilute acid is _________.

$$\mathrm{Ti}^{2+}, \mathrm{Cr}^{2+} \text { and } \mathrm{V}^{2+}$$

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19

The metal that shows highest and maximum number of oxidation state is :

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20

The element which shows only one oxidation state other than its elemental form is :

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21
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A) : In aqueous solutions $\mathrm{Cr}^{2+}$ is reducing while $\mathrm{Mn}^{3+}$ is oxidising in nature.

Reason (R) : Extra stability to half filled electronic configuration is observed than incompletely filled electronic configuration.

In the light of the above statements, choose the most appropriate answer from the options given below :
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22

Choose the correct statements from the following

A. $$\mathrm{Mn}_2 \mathrm{O}_7$$ is an oil at room temperature

B. $$\mathrm{V}_2 \mathrm{O}_4$$ reacts with acid to give $$\mathrm{VO}_2{ }^{2+}$$

C. $$\mathrm{CrO}$$ is a basic oxide

D. $$\mathrm{V}_2 \mathrm{O}_5$$ does not react with acid

Choose the correct answer from the options given below :

JEE Main 2024 (Online) 31st January Evening Shift
23

Identify correct statements from below:

A. The chromate ion is square planar.

B. Dichromates are generally prepared from chromates.

C. The green manganate ion is diamagnetic.

D. Dark green coloured $$\mathrm{K}_2 \mathrm{MnO}_4$$ disproportionates in a neutral or acidic medium to give permanganate.

E. With increasing oxidation number of transition metal, ionic character of the oxides decreases.

Choose the correct answer from the options given below:

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24

The metals that are employed in the battery industries are

A. $$\mathrm{Fe}$$

B. $$\mathrm{Mn}$$

C. $$\mathrm{Ni}$$

D. $$\mathrm{Cr}$$

E. $$\mathrm{Cd}$$

Choose the correct answer from the options given below:

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25

The orange colour of $$\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$$ and purple colour of $$\mathrm{KMnO}_4$$ is due to

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26

Diamagnetic Lanthanoid ions are :

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27

Which of the following acts as a strong reducing agent? (Atomic number: $$\mathrm{Ce}=58, \mathrm{Eu}=63, \mathrm{Gd}=64, \mathrm{Lu}=71$$)

JEE Main 2024 (Online) 29th January Evening Shift
28

Which of the following statements are correct about $$\mathrm{Zn}, \mathrm{Cd}$$ and $$\mathrm{Hg}$$ ?

A. They exhibit high enthalpy of atomization as the d-subshell is full.

B. $$\mathrm{Zn}$$ and $$\mathrm{Cd}$$ do not show variable oxidation state while $$\mathrm{Hg}$$ shows $$+\mathrm{I}$$ and $$+\mathrm{II}$$.

C. Compounds of $$\mathrm{Zn}, \mathrm{Cd}$$ and $$\mathrm{Hg}$$ are paramagnetic in nature.

D. $$\mathrm{Zn}, \mathrm{Cd}$$ and $$\mathrm{Hg}$$ are called soft metals.

Choose the most appropriate from the options given below:

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29

The correct IUPAC name of $$\mathrm{K}_2 \mathrm{MnO}_4$$ is

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30

$$\mathrm{KMnO}_4$$ decomposes on heating at $$513 \mathrm{~K}$$ to form $$\mathrm{O}_2$$ along with

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31

Given below are two statements :

Statement (I) : In the Lanthanoids, the formation $$\mathrm{Ce}^{+4}$$ is favoured by its noble gas configuration.

Statement (II) : $$\mathrm{Ce}^{+4}$$ is a strong oxidant reverting to the common +3 state.

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

JEE Main 2024 (Online) 27th January Evening Shift
32

Choose the correct option having all the elements with $$\mathrm{d}^{10}$$ electronic configuration from the following :

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33

Which of the following electronic configuration would be associated with the highest magnetic moment?

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34

$$\mathrm{NaCl}$$ reacts with conc. $$\mathrm{H}_2 \mathrm{SO}_4$$ and $$\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$$ to give reddish fumes (B), which react with $$\mathrm{NaOH}$$ to give yellow solution (C). (B) and (C) respectively are ;

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35

The electronic configuration for Neodymium is:

[Atomic Number for Neodymium 60]

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36

The pair of lanthanides in which both elements have high third - ionization energy is :

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37

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

Assertion A: $$5 \mathrm{f}$$ electrons can participate in bonding to a far greater extent than $$4 \mathrm{f}$$ electrons

Reason R: $$5 \mathrm{f}$$ orbitals are not as buried as $$4 \mathrm{f}$$ orbitals

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

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38

Prolonged heating is avoided during the preparation of ferrous ammonium sulphate to :

JEE Main 2023 (Online) 10th April Morning Shift
39

Which of the following statements are correct?

(A) The M$$^{3+}$$/M$$^{2+}$$ reduction potential for iron is greater than manganese.

(B) The higher oxidation states of first row d-block elements get stabilized by oxide ion.

(C) Aqueous solution of Cr$$^{2+}$$ can liberate hydrogen from dilute acid.

(D) Magnetic moment of V$$^{2+}$$ is observed between 4.4 - 5.2 BM.

Choose the correct answer from the options given below :

JEE Main 2023 (Online) 10th April Morning Shift
40

Which halogen is known to cause the reaction given below :

$$2 \mathrm{Cu}^{2+}+4 \mathrm{X}^{-} \rightarrow \mathrm{Cu}_{2} \mathrm{X}_{2}(\mathrm{s})+\mathrm{X}_{2}$$

JEE Main 2023 (Online) 8th April Morning Shift
41

In chromyl chloride, the number of d-electrons present on chromium is same as in

(Given at no. of $$\mathrm{Ti}: 22, \mathrm{~V}: 23, \mathrm{Cr}: 24, \mathrm{Mn}: 25, \mathrm{Fe}: 26$$ )

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42

Element not present in Nessler's reagent is :

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43

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

Assertion A : In the complex $$\mathrm{Ni}(\mathrm{CO})_{4}$$ and $$\mathrm{Fe}(\mathrm{CO})_{5}$$, the metals have zero oxidation state.

Reason R : Low oxidation states are found when a complex has ligands capable of $$\pi$$-donor character in addition to the $\sigma$-bonding.

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

JEE Main 2023 (Online) 6th April Evening Shift
44

During the reaction of permanganate with thiosulphate, the change in oxidation of manganese occurs by value of 3. Identify which of the below medium will favour the reaction.

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45

Strong reducing and oxidizing agents among the following, respectively, are :

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46

Which element is not present in Nessler's reagent?

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47

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

Assertion (A) : $$\mathrm{Cu^{2+}}$$ in water is more stable than $$\mathrm{Cu^{+}}$$.

Reason (R) : Enthalpy of hydration for $$\mathrm{Cu^{2+}}$$ is much less than that of $$\mathrm{Cu^{+}}$$.

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

JEE Main 2023 (Online) 1st February Evening Shift
48

Highest oxidation state of Mn is exhibited in $$\mathrm{Mn_2O_7}$$. The correct statements about $$\mathrm{Mn_2O_7}$$ are

(A) Mn is tetrahedrally surrounded by oxygen atoms.

(B) Mn is octahedrally surrounded by oxygen atoms.

(C) Contains Mn-O-Mn bridge.

(D) Contains Mn-Mn bond.

Choose the correct answer from the options given below :

JEE Main 2023 (Online) 1st February Morning Shift
49

When $$\mathrm{Cu}^{2+}$$ ion is treated with $$\mathrm{KI}$$, a white precipitate, $$\mathrm{X}$$ appears in solution. The solution is titrated with sodium thiosulphate, the compound $$\mathrm{Y}$$ is formed. $$\mathrm{X}$$ and $$\mathrm{Y}$$ respectively are :

JEE Main 2023 (Online) 31st January Morning Shift
50

$$\mathrm{Nd^{2+}}$$ = __________

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51

The correct order of basicity of oxides of vanadium is :

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52
Formulae for Nessler's reagent is :
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53
$\mathrm{KMnO}_4$ oxidises $\mathrm{I}^{-}$ in acidic and neutral/faintly alkaline solutions, respectively, to :
JEE Main 2023 (Online) 30th January Evening Shift
54

During the qualitative analysis of $$\mathrm{SO}_{3}^{2-}$$ using dilute $$\mathrm{H}_{2} \mathrm{SO}_{4}, \mathrm{SO}_{2}$$ gas is evolved which turns $$\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$$ solution (acidified with dilute $$\mathrm{H}_{2} \mathrm{SO}_{4}$$) :

JEE Main 2023 (Online) 30th January Morning Shift
55

Given below are two statements :

Statement I : Nickel is being used as the catalyst for producing syn gas and edible fats.

Statement II : Silicon forms both electron rich and electron deficient hydrides.

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

JEE Main 2023 (Online) 29th January Evening Shift
56

The set of correct statements is :

(i) Manganese exhibits +7 oxidation state in its oxide.

(ii) Ruthenium and Osmium exhibit +8 oxidation in their oxides.

(iii) Sc shows +4 oxidation state which is oxidizing in nature.

(iv) Cr shows oxidising nature in +6 oxidation state.

JEE Main 2023 (Online) 29th January Evening Shift
57

An indicator 'X' is used for studying the effect of variation in concentration of iodide on the rate of reaction of iodide ion with $$\mathrm{H_2O_2}$$ at room temp. The indicator 'X' forms blue coloured complex with compound 'A' present in the solution. The indicator 'X' and compound 'A' respectively are :

JEE Main 2023 (Online) 29th January Evening Shift
58

A chloride salt solution acidified with dil.HNO$$_3$$ gives a curdy white precipitate, [A], on addition of AgNO$$_3$$. [A] on treatment with NH$$_4$$OH gives a clear solution B. A and B are respectively :

JEE Main 2023 (Online) 25th January Evening Shift
59

Which one amongst the following are good oxidizing agents?

A. Sm$$^{2+}$$

B. Ce$$^{2+}$$

C. Ce$$^{4+}$$

D. Tb$$^{4+}$$

Choose the most appropriate answer from the options given below :

JEE Main 2023 (Online) 24th January Evening Shift
60

An ammoniacal metal salt solution gives a brilliant red precipitate on addition of dimethylglyoxime. The metal ion is :

JEE Main 2023 (Online) 24th January Morning Shift
61

Which of the following $$3\mathrm{d}$$-metal ion will give the lowest enthalpy of hydration $$\left(\Delta_{\text {hyd }} \mathrm{H}\right)$$ when dissolved in water ?

JEE Main 2022 (Online) 29th July Evening Shift
62

The reaction of zinc with excess of aqueous alkali, evolves hydrogen gas and gives :

JEE Main 2022 (Online) 29th July Morning Shift
63

In following pairs, the one in which both transition metal ions are colourless is :

JEE Main 2022 (Online) 29th July Morning Shift
64

In neutral or faintly alkaline medium, $$\mathrm{KMnO}_{4}$$ being a powerful oxidant can oxidize, thiosulphate almost quantitatively, to sulphate. In this reaction overall change in oxidation state of manganese will be :

JEE Main 2022 (Online) 29th July Morning Shift
65

Match List - I with List - II, match the gas evolved during each reaction.

List - I List - II
(A) $$\left(\mathrm{NH}_{4}\right)_{2} \mathrm{Cr}_{2} \mathrm{O}_{7} \stackrel{\Delta}{\longrightarrow}$$ (I) $$\mathrm{H}_{2}$$
(B) $$\mathrm{KMnO}_{4}+\mathrm{HCl} \rightarrow$$ (II) $$\mathrm{N}_{2}$$
(C) $$\mathrm{Al}+\mathrm{NaOH}+\mathrm{H}_{2} \mathrm{O} \rightarrow$$ (III) $$\mathrm{O}_{2}$$
(D) $$\mathrm{NaNO}_{3} \stackrel{\Delta}{\longrightarrow}$$ (IV) $$\mathrm{Cl}_{2}$$

Choose the correct answer from the options given below :

JEE Main 2022 (Online) 28th July Morning Shift
66

Which of the following has least tendency to liberate $$\mathrm{H}_{2}$$ from mineral acids?

JEE Main 2022 (Online) 28th July Morning Shift
67

In neutral or alkaline solution, $$\mathrm{MnO}_{4}^{-}$$ oxidises thiosulphate to :

JEE Main 2022 (Online) 27th July Evening Shift
68

Given below are two statements.

Statement I : Iron (III) catalyst, acidified $$\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$$ and neutral $$\mathrm{KMnO}_{4}$$ have the ability to oxidise $$\mathrm{I}^{-}$$ to $$\mathrm{I}_{2}$$ independently.

Statement II : Manganate ion is paramagnetic in nature and involves $$\mathrm{p} \pi-\mathrm{p} \pi$$ bonding.

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

JEE Main 2022 (Online) 27th July Morning Shift
69

The total number of $$\mathrm{Mn}=\mathrm{O}$$ bonds in $$\mathrm{Mn}_{2} \mathrm{O}_{7}$$ is __________.

JEE Main 2022 (Online) 27th July Morning Shift
70

The dark purple colour of $$\mathrm{KMnO}_{4}$$ disappears in the titration with oxalic acid in acidic medium. The overall change in the oxidation number of manganese in the reaction is :

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71

The electronic configuration of Pt (atomic number 78) is :

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72

Which one of the lanthanoids given below is the most stable in divalent form?

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73
The 'f' orbitals are half and completely filled, respectively in lanthanide ions :

[Given : Atomic no. Eu, 63; Sm, 62; Tm, 69; Tb, 65; Yb, 70; Dy, 66]

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74

The most common oxidation state of Lanthanoid elements is +3. Which of the following is likely to deviate easily from +3 oxidation state?

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75

The metal ion (in gaseous state) with lowest spin-only magnetic moment value is :

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76

Cerium (IV) has a noble gas configuration. Which of the following is correct statement about it?

JEE Main 2022 (Online) 25th June Morning Shift
77

Among the following, which is the strongest oxidizing agent?

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78

Metals generally melt at very high temperature. Amongst the following, the metal with the highest melting point will be :

JEE Main 2022 (Online) 24th June Evening Shift
79
In the given chemical reaction, colors of the Fe2+ and Fe3+ ions, are respectively :

5Fe2+ + MnO$$_4^ - $$ + 8H+ $$\to$$ Mn2+ + 4H2O + 5Fe3+
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80
Identify the element for which electronic configuration in +3 oxidation state is [Ar]3d5 :
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81
The Eu2+ ion is a strong reducing agent in spite of its ground state electronic configuration (outermost) : [Atomic number of Eu = 63]
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82
In which one of the following sets all species show disproportionation reaction?
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83
In the structure of the dichromate ion, there is a :
JEE Main 2021 (Online) 31st August Morning Shift
84
Which one of the following lanthanides exhibits +2 oxidation state with diamagnetic nature? (Given Z for Nd = 60, Yb = 70, La = 57, Ce = 58)
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85
The addition of dilute NaOH to Cr3+ salt solution will give :
JEE Main 2021 (Online) 27th August Evening Shift
86
Potassium permanganate on heating at 513 K gives a product which is :
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87
The nature of oxides V2O3 and CrO is indexed as 'X' and 'Y' type respectively. The correct set of X and Y is :
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88
Which one of the following when dissolved in water gives coloured solution in nitrogen atmosphere?
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89
The spin only magnetic moments (in BM) for free Ti3+, V2+ and Sc3+ ions respectively are :

(At.No. Sc : 21, Ti : 22, V : 23)
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90
Which one of the following metals forms interstitial hydride easily?
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91
The correct order of following 3d metal oxides, according to their oxidation numbers is :

(a) CrO3, (b) Fe2O3, (c) MnO2, (d) V2O5, (e) Cu2O
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92
The set having ions which are coloured and paramagnetic both is :
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93
The oxide that shows magnetic property is :
JEE Main 2021 (Online) 18th March Evening Shift
94
Match List - I with List - II

List - I
List - II
(a) Chlorophyll (i) Ruthenium
(b) Vitamin-$${B_{12}}$$ (ii) Platinum
(c) Anticancer drug (iii) Cobalt
(d) Grubbs catalyst (iv) Magnesium


Choose the most appropriate answer from the options given below :
JEE Main 2021 (Online) 18th March Morning Shift
95
The common positive oxidation states for an element with atomic number 24, are :
JEE Main 2021 (Online) 17th March Evening Shift
96
What is the spin-only magnetic moment value (BM) of a divalent metal ion with atomic number 25, in it's aqueous solution?
JEE Main 2021 (Online) 17th March Morning Shift
97
Given below are two statements :

Statement I : Potassium permanganate on heating at 573K forms potassium manganate.

Statement II : Both potassium permanganate and potassium manganate are tetrahedral and paramagnetic in nature.

In the light of the above statements, choose the most appropriate answer from the options given below :
JEE Main 2021 (Online) 17th March Morning Shift
98
Fex2 and Fey3 are known when x and y are :
JEE Main 2021 (Online) 16th March Evening Shift
99
Arrange the following metal complex/compounds in the increasing order of spin only magnetic moment. Presume all the three, high spin system.

(Atomic numbers Ce = 58, Gd = 64 and Eu = 63)

(a) (NH4)2[Ce(NO3)6]

(b) Gd(NO3)3 and

(c) Eu(NO3)3
JEE Main 2021 (Online) 16th March Evening Shift
100
Given below are two statements :

Statement I : The Eo value for Ce4+ / Ce3+ is + 1.74 V.

Statement II : Ce is more stable in Ce4+ state than Ce3+ state.

In the light of the above statements, choose the most appropriate answer from the options given below :
JEE Main 2021 (Online) 16th March Morning Shift
101
Given below are two statement : one is labelled as Assertion A and the other is labelled as Reason R :

Assertion A : Size of Bk3+ ion is less than Np3+ ion.

Reason R : The above is a consequence of the lanthanoid contraction.

In the light of the above statements, choose the correct answer from the options given below :
JEE Main 2021 (Online) 16th March Morning Shift
102
Which one of the following lanthanoids does not form MO2? [M is lanthanoid metal]
JEE Main 2021 (Online) 26th February Morning Shift
103
Given below are two statements :

Statement I : CeO2 can be used for oxidation of aldehydes and ketones.

Statement II : Aqueous solution of EuSO4 is a strong reducing agent.

In the light of the above statements, choose the correct answer from the options given below :
JEE Main 2021 (Online) 25th February Morning Shift
104
In which of the following pairs, the outer most electronic configuration will be the same?
JEE Main 2021 (Online) 25th February Morning Shift
105
The incorrect statement among the following is :
JEE Main 2021 (Online) 24th February Evening Shift
106
What is the correct order of the following elements with respect to their density?
JEE Main 2021 (Online) 24th February Evening Shift
107
Given below are two statements :

Statement I : Colourless cupric metaborate is reduced to cuprous metaborate in a luminous flame.

Statement II : Cuprous metaborate is obtained by heating boric anhydride and copper sulphate in a non-luminous flame.

In the light of the above statements, choose the most appropriate answer from the options given below.
JEE Main 2021 (Online) 24th February Morning Shift
108
Mischmetal is an alloy consisting mainly of :
JEE Main 2020 (Online) 6th September Evening Slot
109
The set that contains atomic numbers of only transition elements, is :
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110
The lanthanoid that does NOT show +4 oxidation state is :
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111
In the sixth period, the orbitals that are filled are :
JEE Main 2020 (Online) 5th September Morning Slot
112
The correct electronic configuration and spin-only
magnetic moment (BM) of Gd3+ (Z = 64), respectively, are :
JEE Main 2020 (Online) 5th September Morning Slot
113
The incorrect statement(s) among (a) - (c) is (are)

(a) W(VI) is more stable than Cr(VI).

(b) In the presence of HCl, permanganate titrations provide satisfactory results.

(c) Some lanthanoid oxides can be used as phosphors.
JEE Main 2020 (Online) 4th September Evening Slot
114
The elements with atomic numbers 101 and 104 belong to, respectively :
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115
The incorrect statement is :
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116
5 g of zinc is treated separately with an excess of

(a) dilute hydrochloric acid and
(b) aqueous sodium hydroxide.

The ratio of the volumes of H2 evolved in these two reactions is :
JEE Main 2020 (Online) 9th January Evening Slot
117
The atomic radius of Ag is closed to :
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118
The pair that has similar atomic radii is :
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119
The correct order of the first ionization enthalpies is :
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120
The INCORRECT statement is :
JEE Main 2019 (Online) 10th April Evening Slot
121
The highest possible oxidation states of uranium and plutonium, respectively are :
JEE Main 2019 (Online) 10th April Evening Slot
122
Consider the hydrated ions of Ti2+, V2+, Ti3+, and Sc3+. The correct order of their spin-only magnetic moments is :
JEE Main 2019 (Online) 10th April Morning Slot
123
The maximum number of possible oxidation states of actinoides are shown by :
JEE Main 2019 (Online) 9th April Evening Slot
124
The statement that is INCORRECT about the interstitial compounds is :
JEE Main 2019 (Online) 8th April Evening Slot
125
The correct order of atomic radii is :
JEE Main 2019 (Online) 12th January Evening Slot
126
$$\underline A \,\,\buildrel {4KOH,{O_2}} \over \longrightarrow \,\,\mathop {2\underline B }\limits_{\left( {Green} \right)} \,\, + \,\,2{H_2}O$$

$$3\underline B \,\,\buildrel {4HCl} \over \longrightarrow \,\,\mathop {2\underline C }\limits_{\left( {Purple} \right)} \,\, + \,\,Mn{O_2} + 2{H_2}O$$

$$2\underline C \,\,\buildrel {{H_2}O.KI} \over \longrightarrow \,\,\mathop {2\underline A }\limits_{\left( {Purple} \right)} \,\, + \,\,2KOH\,\, + \,\,\underline D $$

In the above sequence of reactions, $${\underline A }$$ and $${\underline D }$$, respectively, are :
JEE Main 2019 (Online) 11th January Evening Slot
127
The element that usually does NOT show variable oxidation states is :
JEE Main 2019 (Online) 11th January Morning Slot
128
The 71st electron of an element X with an atomic number of 71 enters into the orbital :
JEE Main 2019 (Online) 10th January Evening Slot
129
The effect of lanthanoid contraction in the lanthanoid series of elements by and large means :
JEE Main 2019 (Online) 10th January Morning Slot
130
Wilkinson catalyst is : (Et = C2H5)
JEE Main 2019 (Online) 10th January Morning Slot
131
The transition element that has lowest enthalpy of atomisation, is :
JEE Main 2019 (Online) 9th January Evening Slot
132
The incorrect statement is :
JEE Main 2018 (Online) 16th April Morning Slot
133
When XO2 is fused with an alkali metal hydroxide in presence of an oxidizing agent such as KNO3 ; a dark green product is formed which disproportioates in acidic solution to afforda dark purple solution. X is :
JEE Main 2018 (Online) 16th April Morning Slot
134
Which of the following ions does not liberate hydrogen gas on reaction with dilute acids ?
JEE Main 2017 (Online) 9th April Morning Slot
135
The pair of compounds having metals in their highest oxidation state is :
JEE Main 2017 (Online) 8th April Morning Slot
136
In the following reactions, ZnO is respectively acting as a/an :

(a) ZnO + Na2O $$\to$$ Na2ZnO2

(b) ZnO + CO2 $$\to$$ ZnCO3
JEE Main 2017 (Offline)
137
The transition metal ions responsible for color in ruby and emerald are, respectively :
JEE Main 2016 (Online) 10th April Morning Slot
138
Which one of the following species is stable in aqueous solution?
JEE Main 2016 (Online) 9th April Morning Slot
139
The reaction of zinc with dilute and concentrated nitric acid, respectively, produces :
JEE Main 2016 (Offline)
140
Which of the following compounds is metallic and ferromagnetic ?
JEE Main 2016 (Offline)
141
The colour of KMnO4 is due to :
JEE Main 2015 (Offline)
142
Match the catalysts to the correct processes :

Catalyst Process
(A) TiCl3 (i) Wacker process
(B) PdCl2 (ii) Ziegler - Natta
polymerization
(C) CuCl2 (iii) Contact process
(D) V2O5 (iv) Deacon's process
JEE Main 2015 (Offline)
143
Which series of reactions correctly represents chemical relations related to iron and its compound?
JEE Main 2014 (Offline)
144
Four successive members of the first row transition elements are listed below with atomic numbers. Which one of them is expected to have the highest $$E_{{M^{3 + }}/{M^{2 + }}}^0$$ value?
JEE Main 2013 (Offline)
145
Which of the following arrangements does not represent the correct order of the property stated against it?
JEE Main 2013 (Offline)
146
Iron exhibits + 2 and +3 oxidation states. Which of the following statements about iron is incorrect?
AIEEE 2012
147
The outer electron configuration of $$Gd$$ (Atomic No. $$64$$) is :
AIEEE 2011
148
In context of the lanthanoids, which of the following statements is not correct?
AIEEE 2011
149
Knowing that the Chemistry of lanthanoids (Ln) is dominated by its +3 oxidation state, which of the following statements is incorrect?
AIEEE 2009
150
In context with the transition elements, which of the following statements is incorrect ?
AIEEE 2009
151
Amount of oxalic acid present in a solution can be determined by its titration with $$KMn{O_4}$$ solution in the presence of $${H_2}S{O_4}.$$ The titration gives unsatisfactory result when carried out in the presence of $$HCl,$$ because $$HCl$$ :
AIEEE 2008
152
Larger number of oxidation states are exhibited by the actinoids than those by the lanthanoids, the main reason being :
AIEEE 2008
153
Identify the incorrect statement among the following :
AIEEE 2007
154
The actinoids exhibits more number of oxidation states in general than the lanthanoids. This is because :
AIEEE 2007
155
Lanthanoid contraction is caused due to :
AIEEE 2006
156
A metal, $$M$$ forms chlorides in its $$+2$$ and $$+4$$ oxidation states. Which of the following statements about these chlorides is correct?
AIEEE 2006
157
The “spin-only” magnetic moment [in units of Bohr magneton, (µB)] of Ni2+ in aqueous solution would be : (Atomic number of Ni = 28)
AIEEE 2006
158
Calomel $$\left( {H{g_2}C{l_2}} \right)$$ on reaction with ammonium hydroxide gives :
AIEEE 2005
159
On heating mixture of $$C{u_2}O$$ and $$C{u_2}S$$ will give :
AIEEE 2005
160
The oxidation state of chromium in the final product formed the reaction between $$K{\rm I}$$ and acidified potassium dichromate solution is :
AIEEE 2005
161
The lanthanide contraction is responsible for the fact that :
AIEEE 2005
162
Which of the following factors may be regarded as the main cause of lanthanide contraction?
AIEEE 2005
163
Cerium (Z = 58) is an important member of the lanthanoids. Which of the following statements about cerium is incorrect?
AIEEE 2004
164
Of the following outer electronic configurations of atoms, the highest oxidation state is achieved by which one of them?
AIEEE 2004
165
Excess of KI reacts with CuSO4 solution and then Na2S2O3 solution is added to it. Which of the statements is incorrect for this reaction?
AIEEE 2004
166
For making good quality mirrors, plates of float glass are used. These are obtained by floating molten glass over a liquid metal which does not solidify before glass. The metal used can be :
AIEEE 2003
167
The number of d-electrons retained in Fe2+ (At no of Fe = 26) ion is :
AIEEE 2003
168
A red solid is insolvable in water. However it becomes soluble if some $$K{\rm I}$$ is added to water. Heating the red solid in a test tube results in liberation of some violet colored fumes and droplets of a metal appear on the cooler parts of the test tube. The red solid is :
AIEEE 2003
169
Which one of the following statements is correct?
AIEEE 2003
170
The radius of La3+ (Atomic number of La = 57) is 1.06 Å. Which one of the following given values will be closest to the radius of Lu3+ (Atomic number of Lu = 71) ?
AIEEE 2003
171
Which one of the following nitrates will leave behind a metal on strong heating?
AIEEE 2003
172
The atomic numbers of vanadium (V), Chromium (Cr), manganese (Mn) and iron (Fe) are respectively 23, 24, 25 and 26. Which one of these may be expected to have the highest second ionization enthalpy?
AIEEE 2003
173
What would happen when a solution of potassium chromate is treated with an excess of dilute nitric acid?
AIEEE 2003
174
When KMnO4 acts as an oxidising agent and ultimately forms [MnO4]-2, MnO2, Mn2O3, Mn+2 then the number of electrons transferred in each case respectively is :
AIEEE 2002
175
Which of the following ions has the maximum magnetic moment?
AIEEE 2002
176
How do we differentiate between Fe3+ and Cr3+ in group III?
AIEEE 2002
177
Most common oxidation states of Ce (cerium) are :
AIEEE 2002

Numerical

1

The molar mass of the water insoluble product formed from the fusion of chromite ore (FeCr₂O₄) with Na₂CO₃ in presence of O₂ is ___________ g mol⁻¹.

JEE Main 2025 (Online) 29th January Morning Shift
2
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
3

Niobium $(\mathrm{Nb})$ and ruthenium $(\mathrm{Ru})$ have " $x$ " and " $y$ " number of electrons in their respective 4 d orbitals. The value of $x+y$ is __________.

JEE Main 2025 (Online) 22nd January Evening Shift
4

A transition metal '$$\mathrm{M}$$' among $$\mathrm{Sc}, \mathrm{Ti}, \mathrm{V}, \mathrm{Cr}, \mathrm{Mn}$$ and $$\mathrm{Fe}$$ has the highest second ionisation enthalpy. The spin-only magnetic moment value of $$\mathrm{M}^{+}$$ ion is _______ BM (Near integer)

(Given atomic number $$\mathrm{Sc}: 21, \mathrm{Ti}: 22, \mathrm{~V}: 23, \mathrm{Cr}: 24, \mathrm{Mn}: 25, \mathrm{Fe}: 26$$)

JEE Main 2024 (Online) 9th April Evening Shift
5

Number of colourless lanthanoid ions among the following is __________.

$$\mathrm{Eu}^{3+}, \mathrm{Lu}^{3+}, \mathrm{Nd}^{3+}, \mathrm{La}^{3+}, \mathrm{Sm}^{3+}$$

JEE Main 2024 (Online) 9th April Morning Shift
6

Among $$\mathrm{VO}_2^{+}, \mathrm{MnO}_4^{-}$$ and $$\mathrm{Cr}_2 \mathrm{O}_7^{2-}$$, the spin-only magnetic moment value of the species with least oxidising ability is __________ BM (Nearest integer).

(Given atomic member $$\mathrm{V}=23, \mathrm{Mn}=25, \mathrm{Cr}=24$$)

JEE Main 2024 (Online) 6th April Evening Shift
7

Among $$\mathrm{CrO}, \mathrm{Cr}_2 \mathrm{O}_3$$ and $$\mathrm{CrO}_3$$, the sum of spin-only magnetic moment values of basic and amphoteric oxides is _________ $$10^{-2} \mathrm{BM}$$ (nearest integer).

(Given atomic number of $$\mathrm{Cr}$$ is 24 )

JEE Main 2024 (Online) 6th April Morning Shift
8

The fusion of chromite ore with sodium carbonate in the presence of air leads to the formation of products $$\mathrm{A}$$ and $$\mathrm{B}$$ along with the evolution of $$\mathrm{CO}_2$$. The sum of spin-only magnetic moment values of A and B is _________ B.M. (Nearest integer)

[Given atomic number : $$\mathrm{C}: 6, \mathrm{Na}: 11, \mathrm{O}: 8, \mathrm{Fe}: 26, \mathrm{Cr}: 24$$]

JEE Main 2024 (Online) 5th April Evening Shift
9

JEE Main 2024 (Online) 5th April Morning Shift Chemistry - d and f Block Elements Question 21 English

In a borax bead test under hot condition, a metal salt (one from the given) is heated at point B of the flame, resulted in green colour salt bead. The spin-only magnetic moment value of the salt is _______ BM (Nearest integer) [Given atomic number of $$\mathrm{Cu}=29, \mathrm{Ni}=28, \mathrm{Mn}=25, \mathrm{Fe}=26$$]

JEE Main 2024 (Online) 5th April Morning Shift
10

A first row transition metal with highest enthalpy of atomisation, upon reaction with oxygen at high temperature forms oxides of formula $$\mathrm{M}_2 \mathrm{O}_{\mathrm{n}}$$ (where $$\mathrm{n}=3,4,5$$). The 'spin-only' magnetic moment value of the amphoteric oxide from the above oxides is _________ $$\mathrm{BM}$$ (near integer)

(Given atomic number: $$\mathrm{Sc}: 21, \mathrm{Ti}: 22, \mathrm{~V}: 23, \mathrm{Cr}: 24, \mathrm{Mn}: 25, \mathrm{Fe}: 26, \mathrm{Co}: 27, \mathrm{Ni}: 28, \mathrm{Cu}: 29, \mathrm{Zn}: 30$$)

JEE Main 2024 (Online) 4th April Evening Shift
11

Consider the following reaction

$$\mathrm{MnO}_2+\mathrm{KOH}+\mathrm{O}_2 \rightarrow \mathrm{A}+\mathrm{H}_2 \mathrm{O} \text {. }$$

Product '$$\mathrm{A}$$' in neutral or acidic medium disproportionate to give products '$$\mathrm{B}$$' and '$$\mathrm{C}$$' along with water. The sum of spin-only magnetic moment values of $$\mathrm{B}$$ and $$\mathrm{C}$$ is ________ BM. (nearest integer) (Given atomic number of $$\mathrm{Mn}$$ is 25)

JEE Main 2024 (Online) 4th April Morning Shift
12

Number of metal ions characterized by flame test among the following is ________.

$$\mathrm{Sr}^{2+}, \mathrm{Ba}^{2+}, \mathrm{Ca}^{2+}, \mathrm{Cu}^{2+}, \mathrm{Zn}^{2+}, \mathrm{Co}^{2+}, \mathrm{Fe}^{2+}$$

JEE Main 2024 (Online) 30th January Evening Shift
13

Total number of ions from the following with noble gas configuration is _________.

$$\mathrm{Sr}^{2+}(z=38), \mathrm{Cs}^{+}(z=55), \mathrm{La}^{2+}(z=57), \mathrm{Pb}^{2+}(z=82), \mathrm{Yb}^{2+}(z=70)$$ and $$\mathrm{Fe}^{2+}(z=26)$$

JEE Main 2024 (Online) 27th January Evening Shift
14
In Chromyl chloride, the oxidation state of chromium is $(+)$ _______________.
JEE Main 2023 (Online) 15th April Morning Shift
15
The total change in the oxidation state of manganese involved in the reaction of $\mathrm{KMnO}_{4}$ and potassium iodide in the acidic medium is ____________.
JEE Main 2023 (Online) 15th April Morning Shift
16

Among following compounds, the number of those present in copper matte is ___________.

A. $$\mathrm{CuCO_{3}}$$

B. $$\mathrm{Cu_{2}S}$$

C. $$\mathrm{Cu_{2}O}$$

D. $$\mathrm{FeO}$$

JEE Main 2023 (Online) 1st February Evening Shift
17

The number of electrons involved in the reduction of permanganate to manganese dioxide in acidic medium is _____________.

JEE Main 2023 (Online) 30th January Morning Shift
18

How many of the following metal ions have similar value of spin only magnetic moment in gaseous state? ______________

(Given : Atomic number V, 23; Cr, 24; Fe, 26; Ni, 28)

V$$^{3+}$$, Cr$$^{3+}$$, Fe$$^{2+}$$, Ni$$^{3+}$$

JEE Main 2023 (Online) 25th January Morning Shift
19

The disproportionation of $$\mathrm{MnO}_{4}^{2-}$$ in acidic medium resulted in the formation of two manganese compounds $$\mathrm{A}$$ and $$\mathrm{B}$$. If the oxidation state of $$\mathrm{Mn}$$ in $$\mathrm{B}$$ is smaller than that of A, then the spin-only magnetic moment $$(\mu)$$ value of B in BM is __________. (Nearest integer)

JEE Main 2022 (Online) 28th July Morning Shift
20

The spin-only magnetic moment value of the compound with strongest oxidizing ability among $$\mathrm{MnF}_{4}, \mathrm{MnF}_{3}$$ and $$\mathrm{MnF}_{2}$$ is ____________ B.M. [nearest integer]

JEE Main 2022 (Online) 26th July Evening Shift
21

Among Co3+, Ti2+, V2+ and Cr2+ ions, one if used as a reagent cannot liberate H2 from dilute mineral acid solution, its spin-only magnetic moment in gaseous state is ___________ B.M. (Nearest integer)

JEE Main 2022 (Online) 25th July Morning Shift
22

Spin only magnetic moment of [MnBr6]4$$-$$ is _________ B.M. (round off to the closest integer)

JEE Main 2022 (Online) 29th June Evening Shift
23

For the reaction given below :

CoCl3 . xNH3 + AgNO3 (aq) $$\to$$

If two equivalents of AgCl precipitate out, then the value of x will be _____________.

JEE Main 2022 (Online) 29th June Evening Shift
24

The number of terminal oxygen atoms present in the product B obtained from the following reaction is _____________.

FeCr2O4 + Na2CO3 + O2 $$\to$$ A + Fe2O3 + CO2

A + H+ $$\to$$ B + H2O + Na+

JEE Main 2022 (Online) 29th June Morning Shift
25

An acidified manganate solution undergoes disproportionation reaction. The spin-only magnetic moment value of the product having manganese in higher oxidation state is _____________ B.M. (Nearest integer)

JEE Main 2022 (Online) 29th June Morning Shift
26

The number of statements correct from the following for Copper (at. no. 29) is/are ____________.

(A) Cu(II) complexes are always paramagnetic.

(B) Cu(I) complexes are generally colourless

(C) Cu(I) is easily oxidized

(D) In Fehling solution, the active reagent has Cu(I)

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

The spin-only magnetic moment value of the most basic oxide of vanadium among V2O3, V2O4 and V2O5 is _____________ B.M. (Nearest integer)

JEE Main 2022 (Online) 26th June Morning Shift
28

Manganese (VI) has ability to disproportionate in acidic solution. The difference in oxidation states of two ions it forms in acidic solution is ____________.

JEE Main 2022 (Online) 24th June Evening Shift
29

The difference in oxidation state of chromium in chromate and dichromate salts is ___________.

JEE Main 2022 (Online) 24th June Morning Shift
30
The value of magnetic quantum number of the outermost electron of Zn+ ion is ______________.
JEE Main 2021 (Online) 31st August Evening Shift
31
The number of f electrons in the ground state electronic configuration of Np (Z = 93) is ___________. (Nearest integer)
JEE Main 2021 (Online) 27th August Morning Shift
32
The number of 4f electrons in the ground statement electronic configuration of Gd2+ is ___________. [Atomic number of Gd = 64]
JEE Main 2021 (Online) 26th August Morning Shift
33
Number of electrons present in 4f orbital of Ho3+ ion is ____________. (Given Atomic No. of Ho = 67)
JEE Main 2021 (Online) 25th July Evening Shift
34
Number of electrons that Vanadium (Z = 23) has in p-orbitals is equal to _____________
JEE Main 2021 (Online) 22th July Evening Shift
35
In the ground state of atomic Fe(Z = 26), the spin-only magnetic moment is ____________ $$\times$$ 10$$-$$1 BM. (Round off to the Nearest Integer). [Given : $$\sqrt 3 $$ = 1.73, $$\sqrt 2 $$ = 1.41 ]
JEE Main 2021 (Online) 17th March Evening Shift
36
In mildly alkaline medium, thiosulphate ion is oxidized by $$MnO_4^ - $$ to "A". The oxidation state of sulphur in "A" is __________.
JEE Main 2021 (Online) 26th February Evening Shift
37
The sum of the total number of bonds between chromium and oxygen atoms in chromate and dichromate ions is ____________.
JEE Main 2020 (Online) 9th January Evening Slot
38
Consider the following reactions :

$$NaCl{\rm{ }} + {\rm{ }}{K_2}C{r_2}{O_7} + \mathop {{H_2}S{O_4}}\limits_{(conc.)} $$$$ \to $$ (A) + side products

(A) + NaOH $$ \to $$ (B) + Side products

$$\left( B \right){\rm{ }} + \mathop {{H_2}S{O_4}}\limits_{(dilute)} + {\rm{ }}{H_2}{O_2}$$ $$ \to $$ (C) + Side products

The sum of the total number of atoms in one molecule each of (A) and (B) and (C) is
JEE Main 2020 (Online) 7th January Evening Slot

MCQ (More than One Correct Answer)

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