A metal nitrate reacts with `KI` to give a black precipitate which on addition of excess of `KI` convert into orange colour solution. The cation of metal nitrate is

Options

A. `Hg^(2+)`
B. `Bi^(3+)`
C. `Pb^(2+)`
D. `Cu^(+)`

Answer

B

Explanation

`Bi(NO_(3))_(3)(aq)+3KI(aq)tounderset(BiI_(3)(s))+3KNO_(3)(aq),BiI_(3)(s)+KI(aq)to underset("Orange")(K[BiI_(4)])`