Which halogen is known to cause the reaction given below: 2Cu^2+… — Solution | JEE Chemistry

MCQEasyJEE 2023Group 17 Elements

Which halogen is known to cause the reaction given below: $2Cu^{2+} + 4X^- \to Cu_2X_2(s) + X_2$

Answer

Correct answer:D

Standard Method

Given: The reaction is

2Cu^{2+} + 4I^- \to Cu_2I_2 + I_2

Find: Which halogen can cause the given reaction.

The reaction involves reduction of $Cu^{2+}$ to $Cu^+$ and simultaneous oxidation of $I^-$ to $I_2$ , forming precipitated $Cu_2I_2$ .

Among the halides, only iodide ions have sufficient reducing strength to reduce $Cu^{2+}$ to $Cu^+$ in this way:

2Cu^{2+} + 4I^- \to Cu_2I_2(s) + I_2

Therefore, the halogen corresponding to this reaction is iodine. The correct option is D.

Assuming all halide ions behave identically with $Cu^{2+}$ is incorrect because their reducing strengths differ. Check which halide can actually reduce $Cu^{2+}$ to $Cu^+$ .
Confusing the halogen $X_2$ with the halide ion $X^-$ leads to wrong reasoning. The reacting species is the halide ion, which gets oxidized to the halogen.

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