A solutionf of a metal ion when treated with KI gives a red precipitate which dissolves in excess KI to give a colourless solution.Moreover, the solution of metal ion on treatment with a solution of cobalt (II) thiocyanate gives rise to a deep-blue crystalline precipitate. The metal ions is

Options

A. `Pb^(2+)`
B. `Hg^(2+)`
C. `Cu^(2+)`
D. `CO^(2+)`

Answer

B

Explanation

`Hg^(2+)+2I^(ɵ)toHgI_2darr` (scarlet red precipitate)
`HgI_2+2I^(ɵ)to[HgI_4]^(2-)`
`Hg^(2+)+Co(SCN)_2toHg(SCN)_2darr+Co_^(2+)`