For the balanced redox reaction :

$a{\mathrm{NO}}_3^{-}+b{\mathrm{Cu}}_2\mathrm{O}+c{\mathrm{H}}^{+}⟶d\mathrm{NO}+e{\mathrm{Cu}}^{2+}+{\mathrm{H}}_2\mathrm{O}$

where a, b, c, d and e are stoichiometric coefficients if 'e' is 14, then the value of 'e' is: 

$\begin{array}{l}3{\mathrm{e}}^{-}+{\mathrm{NO}}_3+4{\mathrm{H}}^{+}\stackrel{\text{ Redoxtion }}{\to }\mathrm{NO}+{\mathrm{H}}_2\mathrm{O}\\ {\mathrm{Cu}}_2\mathrm{O}+2{\mathrm{H}}^{+}\stackrel{\text{ oxidation }}{\to }2{\mathrm{Cu}}^{2+}+{\mathrm{H}}_2\mathrm{O}+2{\mathrm{e}}^{-}\\ 6{\mathrm{e}}^{-}+2{\mathrm{NO}}_3^{-}+8{\mathrm{H}}^{+}\to 2\mathrm{NO}+4{\mathrm{H}}_2\mathrm{O}\\ 3{\mathrm{Cu}}_2\mathrm{O}+6{\mathrm{H}}^{+}\to 6{\mathrm{Cu}}^{2+}+3{\mathrm{H}}_2\mathrm{O}+6{\mathrm{e}}^{-}\end{array}$

Total Equation is

$2{\mathrm{NO}}_3^{-}+3{\mathrm{Cu}}_2\mathrm{O}+14{\mathrm{H}}^{+}\to 2\mathrm{NO}+6{\mathrm{Cu}}^{2+}+7{\mathrm{H}}_2\mathrm{O}$

For the balanced redox reaction : $a{\mathrm{NO}}_3^{-}+b{\mathrm{Cu}}_2\mathrm{O}+c{\mathrm{H}}^{+}\to d\mathrm{NO}+e{\mathrm{Cu}}^{2+}+{\mathrm{H}}_2\mathrm{O}$

where a,b,c,d and e are  stoichiometric coefficients if 'c' is 14, then the ten value of 'e' is 6.