Chemistry - PRACTICAL ORGANIC CHEMISTRY Question with Solution | TestHub

${\mathrm{Na}}_2\mathrm{S}$ and NaCN, if present in the extract, will be decomposed to ${\mathrm{H}}_2\mathrm{S}$ and $\mathrm{HCN}$ by ${\mathrm{HNO}}_3$. $$\begin{array}{rl}& \mathrm{NaCN}+{\mathrm{HNO}}_3⟶{\mathrm{NaNO}}_3+\mathrm{HCN}\\ & {\mathrm{Na}}_2\mathrm{S}+2{\mathrm{HNO}}_3⟶2{\mathrm{NaNO}}_3+{\mathrm{H}}_2\mathrm{S}\end{array}$$ These will escape from the solution and will not interfere with the test for halogens.