Question

$Zn$ gives $H_2$ gas with $H_{2}S{O}_4$ and $HCl$ but not with $HN{O}_3$ because:

• A. $Zn$ act as oxidising agent when react with $HN{O}_3$
• B. $HN{O}_3$ is weaker acid than $H_{2}S{O}_4$ and $HCl$
• C. in electrochemical series $Zn$ is above hydrogen
• D. $N{O}_3{}^{-}$ is reduced in preference to hydronium ion

Answer 1

The correct option is D $N{O}_3{}^{-}$ is reduced in preference to hydronium ion

In case of $HN{O}_3$, following reaction takes place:

$N{O}_3{}^{-}+2H^{+}+e^{-}\to N{O}_2+H_{2}O$

As $N{O}_3^{-}$ is reduced in preference to hydronium ion, so no $H_2$ will evolve with $HN{O}_3$.