The number of electrons transferred in

$N{O}_3^{-}+4H^{+}+e^{-}\to 2H_{2}O+NO$  is ____

In the given reaction, the number of atoms is same on both side of the reactions but charge is not balanced.

$\underset{+4}{\underbrace{{\mathrm{NO}}_3^{-}+4{\mathrm{H}}^{+}+{\mathrm{ne}}^{-}}}\to \underset{0}{\underbrace{2{\mathrm{H}}_2\mathrm{O}+\mathrm{NO}}}$

To balance the charge, n comes to be 3.

${\mathrm{NO}}_3^{-}+4{\mathrm{H}}^{+}+3{\mathrm{e}}^{-}\to 2{\mathrm{H}}_2\mathrm{O}+\mathrm{NO}$