Question

Excess of KI reacts with $\text{CuS}{\text{O}}_{\text{4}}$ solution and then $\text{N}{\text{a}}_{\text{2}}{\text{S}}_{\text{2}}{\text{O}}_{\text{3}}$ solution is added to it. Which of the statements is incorrect for this reaction?

• A. $\text{C}{\text{u}}_{\text{2}}{\text{I}}_{\text{2}}$ is formed
• B. $\text{Cu}{\text{I}}_2$ is formed
• C. $\text{N}{\text{a}}_{\text{2}}{\text{S}}_{\text{2}}{\text{O}}_{\text{3}}$ is oxidised
• D. Evolved ${\text{I}}_2$ is reduced

Answer 1

Answer: (B)

$CuS{O}_4+2KI\to \underset{\text{unstable}}{Cu{I}_2}+K_{2}S{O}_4$ $2Cu{I}_2\to C{u}_2{I}_2+I_2$
Thus, $\text{Cu}{\text{I}}_{\text{2}}$ is not formed.