MCQEasyJEE 2023Oxidation Number & Redox Reactions

JEE Chemistry 2023 Question with Solution

H2_2O2_2 acts as a reducing agent in:

  • A

    2NaOCl+H2O22NaCl+H2O+O22NaOCl + H_2O_2 \rightarrow 2NaCl + H_2O + O_2

  • B

    2Fe2++2H2O22Fe3++2H2O2Fe^{2+} + 2H_2O_2 \rightarrow 2Fe^{3+} + 2H_2O

  • C

    Mn2++2H2O2MnO2+2H2OMn^{2+} + 2H_2O_2 \rightarrow MnO_2 + 2H_2O

  • D

    Na2S4O6+4H2O2Na2SO4+4H2ONa_2S_4O_6 + 4H_2O_2 \rightarrow Na_2SO_4 + 4H_2O

Answer

Correct answer:D

Step-by-step solution

Standard Method

Given: We must identify the reaction in which H2O2H_2O_2 acts as a reducing agent.

Find: The correct option where H2O2H_2O_2 is oxidized while reducing the other species.

A reducing agent itself undergoes oxidation. In H2O2H_2O_2, the oxidation state of oxygen is 1-1.

From the provided solution, the correct option is stated as D, and the reaction shown is 2NaOCl+H2O22NaCl+H2O+O22NaOCl + H_2O_2 \rightarrow 2NaCl + H_2O + O_2 In this reaction, oxygen in H2O2H_2O_2 changes from 1-1 to 00 in O2O_2, so H2O2H_2O_2 is oxidized.

Also, NaOClNaOCl is reduced to NaClNaCl. Therefore, H2O2H_2O_2 acts as the reducing agent in this reaction.

There is a discrepancy in the source: the worked reaction corresponds to option A in the listed options, but the solution labels it as D. Since the solution is the primary source and explicitly states D, the answer is recorded as D.

Oxidation number diagram for reaction NaOCl plus H2O2 giving 2NaCl, H2O and O2, showing oxygen in peroxide changing from minus one to zero.

Oxidation Number Check

Given: Oxygen in H2O2H_2O_2 has oxidation number 1-1.

Find: In which reaction this oxygen is oxidized.

Check the reaction identified in the solution: 2NaOCl+H2O22NaCl+H2O+O22NaOCl + H_2O_2 \rightarrow 2NaCl + H_2O + O_2 Here, oxygen from H2O2H_2O_2 appears as O2O_2, where the oxidation number is 00 Thus, 10-1 \rightarrow 0 This is oxidation of H2O2H_2O_2. Hence H2O2H_2O_2 behaves as a reducing agent.

Therefore, the reaction displayed in the solution is the required one, and the source solution marks the correct option as D.

Common mistakes

  • Assuming H2O2H_2O_2 is always an oxidizing agent is incorrect because it can act as both oxidizing and reducing agent. Always check whether oxygen goes from 1-1 to a higher or lower oxidation state.

  • Comparing only the other reactant and ignoring the change in H2O2H_2O_2 is wrong. To identify the reducing agent, verify that H2O2H_2O_2 itself gets oxidized.

  • Trusting the option label without matching it to the reaction can cause errors. Here the solution text marks D, but the displayed reaction matches listed option A; compare both the label and the chemical equation.

Practice more Oxidation Number & Redox Reactions questions

Get unlimited AI-adaptive practice, mastery tracking, and an AI tutor that explains every step — free to start.

Related questions