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

Options

A. `Br^(-)`
B. `I^(-)`
C. `NO_(3)^(-)`
D. `NO_(2)^(-)`

Answer

D

Explanation

Nitrite ion liberates `I_(2)` from potassium iodide turning starch blue.
`2NO_(2)^(-)+3l^(-)+4CH_(3)COOH to I_(3)^(-)+2NOuarr+4CH_(3)COO^(-)+2H_(2)O`
`I_(2)`+starch `to` blue colour