Question:
Which of the following compound is added to the sodium extract before addition of silver nitrate for testing of halogens ?
Correct Option: 1
Solution:
$\mathrm{NaCN}+\mathrm{HNO}_{3} \rightarrow \mathrm{NaNO}_{3}+\mathrm{HCN} \uparrow$
$\mathrm{Na}_{2} \mathrm{~S}+\mathrm{HNO}_{3} \rightarrow \mathrm{NaNO}_{3}+\mathrm{H}_{2} \mathrm{~S} \uparrow$
Nilnic acid decomposed $\mathrm{NaCN} \& \mathrm{Na}_{2} \mathrm{~S}$, else they precipitate in test \& misquite the resolve