Question

$Zn$ gives ${H_2}$ gas with ${H_2}S{O_4}$ and $HCl$ but not from $HN{O_3}$
A. $Zn$ acts as an oxidizing agent 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. $NO_3^ -$ is reduced in preference to hydronium ion

Answer 1

$HN{O_3}$ is a strong oxidizing agent and it immediately oxidizes the ${H^ + }$ ion in hydrogen to form water but $NO_3^ -$ ion gets reduced. The oxidizing agent means the species which can oxidize others easily and the reducing agent means the species which can reduce others but itself gets oxidized.

Complete step by step answer:
$Zn$ acts as an oxidizing agent when it reacts with $HN{O_3}$
$HN{O_3}$ is a weaker acid than ${H_2}S{O_4}$ and $HCl$
In the electrochemical series, $Zn$ is above hydrogens $N{O_3}$ reduced in preference to hydronium ion
Zinc gives hydrogen gas with dilute ${H_2}S{O_4}/HCl$ but not with $HN{O_3}$
Because in $HN{O_3}$ , $NO_3^ -$ is reduced to give $NH_4^ +$, ${N_2}O,NO,$ $N{O_2}$ (based upon the concentration of $HNO_3^{}$)
$Zn$ is on the top position of hydrogen in the electrochemical series. so the $Zn$ displaces ${H_2}$ from dilute ${H_2}S{O_4}$ and $HCl$ with the liberation of $H_2$.

Note:
An oxidizing agent is a reactant that removes electrons from other reactants during a redox reaction. The oxidizing agent typically takes these electrons for itself, thus gaining electrons and being reduced. An oxidizing agent is thus an electron acceptor.Reducing agent is an element or compound that loses an electron to an electron recipient in a redox chemical reaction. A reducing agent is thus oxidized when it loses electrons in the redox reaction. Reducing agents "reduce" oxidizing agents. Oxidizers "oxidize" reducers.