To a metal nitrate, when KI solution is added, a black precipitate is produced at first , on additing excess of KI, orange solution is produced. Identify the meatl ion

Options

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

Answer

B

Explanation

`Bi^(3+)+3I^(-)rarr underset("black")(BiI_(3)darr)`
The precipitate dissolves readily in excess reagent forming `underset("orange coloured")([BiI_(4)]^(-))`
`BiI_(3)+I^(-)rarr underset("tetraiodo bismuthate(III)ion")([BiI_(4)]^(-))`