Q25 / 150 · MHT CET 2026 (13 April Shift 2) · Chemistry
Which of the following reaction is possible at anode?
- A$\text{F}_2 + 2e^- \rightarrow 2\text{F}^-$
- B$2\text{H}^+ + \dfrac{1}{2}\text{O}_2 + 2e^- \rightarrow \text{H}_2\text{O}$
- Correct answerC$\text{Fe}^{2+} \rightarrow \text{Fe}^{3+} + 1e^-$
- D$\text{Cu}^{2+} + 2e^- \rightarrow \text{Cu}(s)$
Solution
At the anode, oxidation takes place. Oxidation is defined as the loss of electrons.
Analyzing the given reactions:
$\text{F}_2 + 2e^- \rightarrow 2\text{F}^-$ involves the gain of electrons, hence it is a reduction reaction.
$2\text{H}^+ + \dfrac{1}{2}\text{O}_2 + 2e^- \rightarrow \text{H}_2\text{O}$ involves the gain of electrons, hence it is a reduction reaction.
$\text{Fe}^{2+} \rightarrow \text{Fe}^{3+} + 1e^-$ involves the loss of an electron, hence it is an oxidation reaction.
$\text{Cu}^{2+} + 2e^- \rightarrow \text{Cu}(s)$ involves the gain of electrons, hence it is a reduction reaction.
Since only the third reaction represents oxidation, it is the only reaction possible at the anode.
Answer: $\text{Fe}^{2+} \rightarrow \text{Fe}^{3+} + 1e^-$
Analyzing the given reactions:
$\text{F}_2 + 2e^- \rightarrow 2\text{F}^-$ involves the gain of electrons, hence it is a reduction reaction.
$2\text{H}^+ + \dfrac{1}{2}\text{O}_2 + 2e^- \rightarrow \text{H}_2\text{O}$ involves the gain of electrons, hence it is a reduction reaction.
$\text{Fe}^{2+} \rightarrow \text{Fe}^{3+} + 1e^-$ involves the loss of an electron, hence it is an oxidation reaction.
$\text{Cu}^{2+} + 2e^- \rightarrow \text{Cu}(s)$ involves the gain of electrons, hence it is a reduction reaction.
Since only the third reaction represents oxidation, it is the only reaction possible at the anode.
Answer: $\text{Fe}^{2+} \rightarrow \text{Fe}^{3+} + 1e^-$
Hence, the correct answer is option: 'C'.