The LaSSaigen's extract is boiled with conc. `HNO_(3)` while testing for halogens. By doing so it `:`

Options

A. helps in the precipitation of AgCl
B. increases the solubility product of AgCl
C. increases the concentration of `NO_(3)^(-)` ions
D. decomposes `Na_(2)S` and NaCN , if formed

Answer

D

Explanation

`Na_(2)S` and NaCN , if present in the extract will be decomposed to `H_(2)S` and HCN by `HNO_(3)` .
`NaCN + HNO_(3) to NaNO_(3) + HCN`
`Na_(2) S + 2HNO_(3) to 2NaNO_(3) + H_(2)S`
These will escape from the solution and will not interfere with the test for the halogens .