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

JEE Main · 2023 · 08 Apr 2023 · Shift 1 · p-Block Elements

Which halogen is known to cause the reaction given below:

2 Cu^{2 +} + 4 X^{-} \to Cu_{2} X_{2} (s) + X_{2}

(A)Only Iodine✓ Correct
(B)Only Bromine
(C)All halogens
(D)Only Chlorine

Answer: (A)

Solution

This is a redox reaction where Cu²⁺ is reduced to Cu⁺ and the halide ion X⁻ is oxidized to X₂. For this reaction to occur, the halide must be a strong enough reducing agent to reduce Cu²⁺. Among the halogens, only iodide (I⁻) is a sufficiently strong reducing agent to accomplish this. The reaction is:

2 Cu^{2 +} + 4 I^{-} \to Cu_{2} I_{2} (s) + I_{2}

. Chloride and bromide are not strong enough reducing agents for this reaction.

JEE Main · 2023 · 08 Apr 2023 · Shift 1 · Single correct option

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