Binding energy can be calculated from the formula,

Binding energy= (Mass defect)  $\left(\frac{931\mathrm{MeV}}{1\mathrm{amu}}\right)$

Nuclear reaction :$7p+7n{\to }_7^{14}\mathrm{N}$

Mass defect $\mathrm{\Delta M}=7{\mathrm{m}}_{\mathrm{p}}+7{\mathrm{m}}_{\mathrm{n}}-{\mathrm{m}}_{\text{nucleus }}$ 

$\begin{array}{l}\therefore \mathrm{\Delta M}=7\left(1.00783\right)+7\left(1.00867\right)-14.00307\mathrm{amu}\\ \Rightarrow \mathrm{\Delta M}=0.11243\mathrm{amu}\end{array}$

Thus binding energy $\mathrm{E}=\mathrm{\Delta M}\times 931.5\mathrm{MeV}$ 

$\therefore \mathrm{E}=0.11243\times 931.5=104.73\mathrm{MeV}$

Binding energy per nucleon $=\frac{104.73}{14}=7.48\mathrm{MeV}$