Question

Sodium nitrite is reacted with $H_2SO_4$ to form $NaHSO_4, HNO_3$, water and $X$. Gold is dissolved in aqua-regia to form water, $AuCl^{-}_4$ and $Y. X$ and $Y$ are respectively

• A. $NO, NO_2$
• B. $NO_2, NO$
• C. $NO , NO$
• D. $\ce{N_2O, NO}$

Answer 1

Answer: (C)

Sodium nitrite is reacted with $H _{2} SO _{4}$ to form $NaHSO _{4}, HNO _{3}$, water and $NO$ gas $(X) .$ Gold is dissolved in aqua-regia to form water, $AuCl _{4}^{-}$ and

NO gas. Thus, here $X$ is $NO$ and $Y$ is $NO$. Reactions involved are as follows :

$\underset{\text { Sodium nitrite}}{ NaNO _{2}}+ H _{2} SO _{4} \longrightarrow NaHSO _{4}+ HNO _{3}+ H _{2} O +\underset{(X)}{ NO }$

$Au (s)+\underbrace{ HNO _{3}+4 HCl }_{\text {Aqua-regia }} \rightleftharpoons AuCl _{4}^{-}+\underset{(Y)}{ NO }+ H _{2} O$