$N \equiv N\,\left( {946\,kJ\,mo{l^{ - 1}}} \right)\,;\,N = N\,\left( {418\,kJ\,mo{l^{ - 1}}} \right)$
$O = O\,\left( {498\,kJ\,mo{l^{ - 1}}} \right)\,;\,N = O\,\left( {607\,kJ\,mo{l^{ - 1}}} \right)$;
$N _2+\frac{1}{2} O _2 \longrightarrow N _2 O$
$( N \equiv N )+\frac{1}{2}( O = O ) \longrightarrow N = N = O$
$\Delta_f H^{\circ}=\Sigma B . E$ of recectants $-\Sigma B . E$ of products
$=\left[( N \equiv N )+\frac{1}{2}( O = O )\right]-[( N = N )+( N =0)]$
$=\left|946+\frac{1}{2}(498)\right|-[418+607 \mid=1195-1025$
$=170$
સસ્પંદન ઊર્જા $=82-170$
$=-88\, kJ\, mol ^{-1}$
[$1 \;\mathrm{L} \text { bar }=100 \;\mathrm{J}$ આપેલ છે.]