Identify the hydrated blue salt which when treated with KI solution, a brown solution is obtained which becomes colourless when treated with hypo solution.

Options

A. `CuSO_(4).5H_(2)O`
B. `ZnSO_(4).7H_(2)O`
C. `FeSO_(4).7H_(2)O`
D. None of these

Answer

A

Explanation

`{:(Cu^(2+)overset(KI)rarrCuI_(2)rarrubrace(Cu_(2)I_(2)+I_(2))_("Brown")),(" "darrNa_(2)S_(2)O_(3)),(" "2NaI+Na_(2)S_(4)O_(6)+Cu_(2)I_(2)darr"white"):}`