Question

What happens when \( \mathrm{H_2O_2} \) is added to an aqueous solution of ferrous sulphate in an acidic medium?

• A. Only $\mathrm{H_2O_2}$ is evolved
• B. $\mathrm{Fe}^{2+}$ is reduced
• C. $\mathrm{Fe}^{2+}$ is oxidized
• D. $\mathrm{H_2O_2}$ is evolved and $\mathrm{Fe}^{2+}$ is oxidized

Hint:

Understanding oxidation-reduction reactions is crucial for predicting chemical behavior in various environments.

Answer 1

The Correct Option is C

Analyze the redox behavior of \( \mathrm{H_2O_2} \) in reaction with \( \mathrm{Fe}^{2+} \).
\[ \mathrm{Fe}^{2+} + \mathrm{H_2O_2} \rightarrow \mathrm{Fe}^{3+} + \mathrm{H_2O} \]

This reaction primarily involves the oxidation of \( \mathrm{Fe}^{2+} \) to \( \mathrm{Fe}^{3+} \) by \( \mathrm{H_2O_2} \), which acts as an oxidizing agent.

Answer 2

To solve this problem, we need to understand the reaction that occurs when hydrogen peroxide (H₂O₂) is added to an aqueous solution of ferrous sulfate (FeSO₄) in an acidic medium.

1. The Reaction Mechanism:
When H₂O₂ is added to an aqueous solution of ferrous sulfate (FeSO₄) in acidic conditions, the reaction proceeds as follows:

\[ \text{Fe}^{2+} + \text{H}_2\text{O}_2 \rightarrow \text{Fe}^{3+} + \text{OH}^- \text{ or } \text{Fe}^{2+} + \text{H}_2\text{O}_2 \rightarrow \text{Fe}^{3+} + \text{H}_2\text{O}. \] This results in the oxidation of Fe²⁺ (iron (II)) to Fe³⁺ (iron (III)) and the reduction of H₂O₂, which leads to the evolution of oxygen gas (O₂). Therefore, Fe²⁺ is oxidized, and H₂O₂ is reduced, producing oxygen and possibly water as products.

2. Analyzing the Options:

Option 1: "Only H₂ is evolved" is incorrect. In this reaction, oxygen gas is evolved, not hydrogen gas (H₂).
Option 2: "Fe²⁺ is reduced" is incorrect. Fe²⁺ is actually oxidized, not reduced, in this reaction.
Option 3: "Fe²⁺ is oxidized" is correct. In the reaction, Fe²⁺ is oxidized to Fe³⁺, and oxygen is evolved from H₂O₂.
Option 4: "H₂ is evolved and Fe²⁺ is oxidized" is incorrect because hydrogen gas (H₂) is not evolved, oxygen gas is released.

3. Conclusion:
Option 3 is the correct answer as it accurately represents the oxidation of Fe²⁺ and the evolution of oxygen gas.

Final Answer:
The correct answer is Option C: "H₂ is evolved and Fe²⁺ is oxidized."