Question

When nitric acid reacts with nitric oxide, a gas is released, which converts $H _{2} S$ into

• A. $SO _{4}^{2-}$
• B. $S ^{2-}$
• C. $S$
• D. $S _{2} O _{5}^{2-}$

Answer 1

Answer: (C)

When nitric acid $\left( HNO _{3}\right)$ reacts with nitric oxide (NO), $NO _{2}$ gas is released which oxidises $H _{2} S$ into sulphur.
The reactions are as follows :
$2 HNO _{3}+ NO \longrightarrow H _{2} O +3 NO _{2} $
$NO _{2}+ H _{2} S \longrightarrow H _{2} O + S + NO$