Solution of a salt in dilute `H_(2)SO_(4)` or acetic and produces deep blue colour with starch iodide solution. The salt contains :

Options

A. `Br^(-)`
B. `I^(-)`
C. `Cl^(-)`
D. `NO_(2)^(-)`

Answer

D

Explanation

Nitrite ion liberates `I_(2)` from potassium iodide turning starch blue.
`2NO_(2)^(-)+3l^(-)+4CH_(3)CO OH to l_(3)^(-) +2NO uarr +4CH_(3)CO O^(-)+2H_(2)O`
`l_(2)` + starch `to` blue colour