Question

$H _2 O _2$ acts as a reducing agent in

• A. $Na _2 S +4 H _2 O _2 \rightarrow Na _2 SO _4+4 H _2 O$
• B. $Mn ^{2+}+2 H _2 O _2 \rightarrow MnO _2+2 H _2 O$
• C. $2 Fe ^{2+}+2 H ^{+}+ H _2 O _2 \rightarrow 2 Fe ^{3+}+2 H _2 O$
• D. $2 NaOCl + H _2 O _2 \rightarrow 2 NaCl + H _2 O + O _2$

Hint:

Hydrogen peroxide is commonly used as a reducing agent, as it can donate electrons and reduce other compounds.

Answer 1

The Correct Option is D

To determine where \(H_2O_2\) acts as a reducing agent, we must identify a reaction where \(H_2O_2\) donates electrons. In chemical terms, a reducing agent is a substance that reduces another substance and itself becomes oxidized, losing electrons in the process.

Let's analyze each option:

\(Na_2 S + 4H_2O_2 \rightarrow Na_2SO_4 + 4H_2O\): In this reaction, \(H_2O_2\) is acting as an oxidizing agent as it oxidizes \(Na_2S\) to \(Na_2SO_4\). Hence, not acting as a reducing agent.

\(Mn^{2+} + 2H_2O_2 \rightarrow MnO_2 + 2H_2O\): In this reaction, \(H_2O_2\) acts as an oxidizing agent by oxidizing \(Mn^{2+}\) to \(MnO_2\). Thus, \(H_2O_2\) is oxidizing, not reducing.

\(2Fe^{2+} + 2H^{+} + H_2O_2 \rightarrow 2Fe^{3+} + 2H_2O\): Here, \(H_2O_2\) oxidizes \(Fe^{2+}\) to \(Fe^{3+}\) and acts as the oxidizing agent, not the reducing agent.

\(2NaOCl + H_2O_2 \rightarrow 2NaCl + H_2O + O_2\): In this reaction, \(H_2O_2\) acts as a reducing agent as it reduces \(NaOCl\) to \(NaCl\) while itself gets oxidized to \(O_2\). Thus, \(H_2O_2\) is indeed acting as a reducing agent.

Thus, the correct answer is: \(2NaOCl + H_2O_2 \rightarrow 2NaCl + H_2O + O_2\), where \(H_2O_2\) is a reducing agent.