Redox Reactions · Chemistry · COMEDK

Start Practice

MCQ (Single Correct Answer)

1
Choose the correct statement.
COMEDK 2025 Morning Shift
2
The concentration and percentage purity of Oxalic acid can be determined by titration with $\mathrm{KMnO}_4$ in presence of dil. $\mathrm{H}_2 \mathrm{SO}_4$. Instead of dil. $\mathrm{H}_2 \mathrm{SO}_4$, dil HCl cannot be used because
COMEDK 2025 Morning Shift
3

Which one of the following options represents the decreasing order of oxidation number of the central atom in:

$$\mathrm{Cr}_2 \mathrm{O}_7^{2-}, \mathrm{Cr} \mathrm{O}_2^{-}, \mathrm{MnO}_4^{-}, \mathrm{BrO}_3^{-}$$

COMEDK 2025 Morning Shift
4

In the redox reaction between $$\mathrm{Cr}_2 \mathrm{O}_7^{2-} / \mathrm{H}^{+}$$ and sulphite ion, what is the number of moles of electrons involved in producing 3.0 moles of the oxidised product?

COMEDK 2024 Evening Shift
5

In the reaction,

$$2 \mathrm{~S}_2 \mathrm{O}_3^{2-}+\mathrm{I}_2 \rightarrow \mathrm{S}_4 \mathrm{O}_6^{2-}+2 \mathrm{I}^{-}$$

COMEDK 2024 Afternoon Shift
6

When $$3.92 \mathrm{~g}$$ of Mohr salt is dissolved in $$100 \mathrm{~mL}$$ of water, and titrated against $$\mathrm{KMnO}_4$$ solution, $$20 \mathrm{~mL}$$ of this solution required $$18 \mathrm{~mL}$$ of $$\mathrm{KMnO}_4$$ for complete oxidation. The strength of $$\mathrm{KMnO}_4$$ is: [Molar mass of Mohr salt is $$392 \mathrm{~g} \mathrm{~mol}^{-1}$$ and $$\mathrm{KMnO}_4$$ is $$158 \mathrm{~g} \mathrm{~mol}^{-1}$$]

COMEDK 2024 Afternoon Shift
7

Identify the oxidation reaction in which acidified $$\mathrm{KMnO}_4$$ is required

COMEDK 2024 Afternoon Shift
8

An inorganic salt comprises of atoms of elements $$\mathrm{A}, \mathrm{B}$$ and $$\mathrm{C}$$. If the oxidation numbers of A, B and $$\mathrm{C}$$ are $$+3,+6$$ and $$-$$2 respectively, what is the possible formula of the compound?

COMEDK 2024 Morning Shift
9

Choose the group of ions / molecules in which none of the species undergo Disproportionation reaction.

COMEDK 2024 Morning Shift
10

In dilute alkaline solution $$\mathrm{MnO}_4^{-}$$ changes to

COMEDK 2023 Morning Shift
11

In neutral medium $$\mathrm{KMnO}_4$$ oxidises $$\mathrm{MnSO}_4$$ to _________

COMEDK 2023 Evening Shift
12

In the given Redox equation, identify the stoichiometric coefficients $$\mathrm{w}, \mathrm{x}, \mathrm{y}$$ and $$\mathrm{z}$$.

$$\mathrm{ClO}_3^{-1}+\mathrm{w} \mathrm{Cl}^{-1}+\mathrm{xH}^{+} \rightarrow \mathrm{y} \mathrm{H}_2 \mathrm{O}+\mathrm{zCl}_2$$

COMEDK 2023 Evening Shift
13

Identify the catalyst used in the reaction between Iodide and persulphate ions.

$$2 \mathrm{I}^{-}+\mathrm{S}_2 \mathrm{O}_8{ }^{2-} \rightarrow \mathrm{I}_2+2 \mathrm{SO}_4{ }^{2-}$$

COMEDK 2023 Evening Shift
14

KMnO$$_4$$ acts as an oxidising agent in acidic medium. The number of moles of KMnO$$_4$$ that will be required to react with one mole of oxalate ions (to form CO$$_2$$) in acidic solution is

COMEDK 2022
15

Which of the following gas readily de-colourises the acidified KMnO$$_4$$ solution?

COMEDK 2022
16

The oxidation number of Cr in CrO$$_5$$ which has the following structure, is

COMEDK 2021 Chemistry - Redox Reactions Question 18 English

COMEDK 2021
17

For decolourisation of 1 mole of KMnO$$_4$$, the moles of H$$_2$$O$$_2$$ required is

COMEDK 2021
18

In the ionic equation,

$$\mathrm{BiO_3^-+6H^++xe^-\rightarrow Bi^{3+}+3H_2O}$$,

the value of x is

COMEDK 2020
19

Carbon forms two oxides which have different compositions. The equivalent mass of which remains constant?

COMEDK 2020
EXAM MAP
Medical
NEETAIIMS
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
Civil Services
UPSC Civil Service
Defence
NDA
Staff Selection Commission
SSC CGL Tier I
CBSE
Class 12