Redox Reactions PYQs - Last 10 Years
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ChemistryPhysical Chemistry2017-2026
Practice 26 COMEDK Chemistry questions from Redox Reactions. Use the year-wise and type-wise breakdown to prioritize recent PYQs, then continue into the question list below.
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2020-2026
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Last 10 Years Redox Reactions Questions
Showing 26 of 26 filtered questions.
1Redox Reactions
In the reaction,
\(\mathrm{Cr}_2 \mathrm{O}_7^{2-}+4 \mathrm{H}_2 \mathrm{O}_2+2 \mathrm{H}^{+} \rightarrow 2 \mathrm{CrO}_5+\mathrm{H}_2 \mathrm{O}\)
The change in oxidation state of Cr is:
\(\mathrm{Cr}_2 \mathrm{O}_7^{2-}+4 \mathrm{H}_2 \mathrm{O}_2+2 \mathrm{H}^{+} \rightarrow 2 \mathrm{CrO}_5+\mathrm{H}_2 \mathrm{O}\)
The change in oxidation state of Cr is:
MCQ+1 / -02026
2Redox Reactions
In the redox reaction, taking place in acidic medium: $\mathrm{X} \mathrm{MnO}_4^{-}(\mathrm{aq})+\mathrm{YSO}_2(\mathrm{~g}) \rightarrow \mathrm{Mn}^{+2}(\mathrm{aq})+\mathrm{HSO}_4^{-}(\mathrm{aq})$, the ratio of $X: Y$ in a stoichiometri...
MCQ+1 / -02026
3Redox Reactions
$x$ moles of $\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ oxidises 1 mole of ferrous oxalate, in acidic medium. Hence ' $x$ ' is:
MCQ+1 / -02026
4Redox Reactions
Which one of the following options represents the decreasing order of oxidation number of the central atom in:
\(\mathrm{Cr}_2 \mathrm{O}_7^{2-}, \mathrm{Cr} \mathrm{O}_2^{-}, \mathrm{MnO}_4^{-}, \mathrm{BrO}_3^{-}\)
\(\mathrm{Cr}_2 \mathrm{O}_7^{2-}, \mathrm{Cr} \mathrm{O}_2^{-}, \mathrm{MnO}_4^{-}, \mathrm{BrO}_3^{-}\)
MCQ+1 / -02025
5Redox Reactions
Choose the correct statement.
MCQ+1 / -02025
6Redox Reactions
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
MCQ+1 / -02025
7Redox Reactions
An example of disproportionation reaction is :
MCQ+1 / -02025
8Redox Reactions
Identify the correct coefficients (a), (b), (c) and (d) in the following equations
i) $\quad \mathrm{xMnO}_4^{--}+$(a) $\mathrm{SO}_3{ }^{2-}+$ (b) $\mathrm{H}^{+} \cdots \longrightarrow \mathrm{xMn}^{2+}+$ (a) $\mathrm{SO}_4{ }^{2-}+$ (c) ...
i) $\quad \mathrm{xMnO}_4^{--}+$(a) $\mathrm{SO}_3{ }^{2-}+$ (b) $\mathrm{H}^{+} \cdots \longrightarrow \mathrm{xMn}^{2+}+$ (a) $\mathrm{SO}_4{ }^{2-}+$ (c) ...
MCQ+1 / -02025
9Redox Reactions
The oxidation number of potassium in $\mathrm{K}_2 \mathrm{O}, \mathrm{K}_2 \mathrm{O}_2$ and $\mathrm{KO}_2$ respectively are:
MCQ+1 / -02025
10Redox Reactions
Given below are 2 statements: one Assertion and the other Reason. Which one of the following options is correct?
Assertion : Sulphur dioxide and Hydrogen peroxide can act as both oxidising and reducing agents but Nitric acid can act as only...
Assertion : Sulphur dioxide and Hydrogen peroxide can act as both oxidising and reducing agents but Nitric acid can act as only...
MCQ+1 / -02025
11Redox Reactions
Choose the group of ions / molecules in which none of the species undergo Disproportionation reaction.
MCQ+1 / -02024
12Redox Reactions
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?
MCQ+1 / -02024
13Redox Reactions
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?
MCQ+1 / -02024
14Redox Reactions
In the reaction,
\(2 \mathrm{~S}_2 \mathrm{O}_3^{2-}+\mathrm{I}_2 \rightarrow \mathrm{S}_4 \mathrm{O}_6^{2-}+2 \mathrm{I}^{-}\)
\(2 \mathrm{~S}_2 \mathrm{O}_3^{2-}+\mathrm{I}_2 \rightarrow \mathrm{S}_4 \mathrm{O}_6^{2-}+2 \mathrm{I}^{-}\)
MCQ+1 / -02024
15Redox Reactions
Identify the oxidation reaction in which acidified \(\mathrm{KMnO}_4\) is required
MCQ+1 / -02024
16Redox Reactions
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 o...
MCQ+1 / -02024
17Redox Reactions
Identify the catalyst used in the reaction between Iodide and persulphate ions.
\(2 \mathrm{I}^{-}+\mathrm{S}_2 \mathrm{O}_8{ }^{2-} \rightarrow \mathrm{I}_2+2 \mathrm{SO}_4{ }^{2-}\)
\(2 \mathrm{I}^{-}+\mathrm{S}_2 \mathrm{O}_8{ }^{2-} \rightarrow \mathrm{I}_2+2 \mathrm{SO}_4{ }^{2-}\)
MCQ+1 / -02023
18Redox Reactions
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{ClO}_3^{-1}+\mathrm{w} \mathrm{Cl}^{-1}+\mathrm{xH}^{+} \rightarrow \mathrm{y} \mathrm{H}_2 \mathrm{O...
MCQ+1 / -02023
19Redox Reactions
In neutral medium \(\mathrm{KMnO}_4\) oxidises \(\mathrm{MnSO}_4\) to _________
MCQ+1 / -02023
20Redox Reactions
In dilute alkaline solution \(\mathrm{MnO}_4^{-}\) changes to
MCQ+1 / -02023
21Redox Reactions
Which of the following gas readily de-colourises the acidified KMnO\(_4\) solution?
MCQ+1 / -02022
22Redox Reactions
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
MCQ+1 / -02022
23Redox Reactions
For decolourisation of 1 mole of KMnO\(_4\), the moles of H\(_2\)O\(_2\) required is
MCQ+1 / -02021
24Redox Reactions
The oxidation number of Cr in CrO\(_5\) which has the following structure, is
MCQ+1 / -02021
25Redox Reactions
Carbon forms two oxides which have different
compositions. The equivalent mass of which
remains constant?
compositions. The equivalent mass of which
remains constant?
MCQ+1 / -02020
26Redox Reactions
In the ionic equation,
\(\mathrm{BiO_3^-+6H^++xe^-\rightarrow Bi^{3+}+3H_2O}\),
the value of x is
\(\mathrm{BiO_3^-+6H^++xe^-\rightarrow Bi^{3+}+3H_2O}\),
the value of x is
MCQ+1 / -02020