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\xrightarrow{{}}\underset{\text{unstable}}{\mathop{Cu{{I}_{2}}}}\,+{{K}_{2}}S{{O}_{4}} $ $ 2Cu{{I}_{2}}\xrightarrow{{}}C{{u}_{2}}{{I}_{2}}+{{I}_{2}} $
Thus, $ \text{Cu}{{\text{I}}_{\text{2}}} $ is not formed.