$N{H_{3(g)}}\, + \,\,\frac{3}{2}\,Cu{O_{(s)}}\, \to \,\,\frac{1}{2}\,{N_{2(g)}}\, + \,\,\frac{3}{2}{H_2}{O_{(\ell )}}\, + \,\,\frac{3}{2}\,C{u_{(s)}}.$ ......$J$
\(\Delta \,H\,\, = \,\,\Sigma \,\,{H_{\ Products}}\,\, - \,\,\,\Sigma \,{H_{\operatorname{Reactants}}}\)
\(\because \,\,H_{element}^ \circ \,\, = \,\,0\)
\(\therefore \,\,\Delta \,H\,\, = \,\,\frac{3}{2}\,H_{{H_2}O}^o \,\, - \,\,H_{N{H_3}}^o \, - \,\,\frac{3}{2}\,H_{CuO}^o \)
\( = \,\,\frac{3}{2}\,\, \times \,\,( - 285)\, - \,( - 46)\, - \,\,\frac{3}{2}\,( - 155)\,\,\,\,\,\,\,\,\,\,\, = \,\, - 149\,\,KJ\)
\(\because \,\,17\,\,gm\,\,N{H_3}\) ના ફેરફાર જોતાં \(\Delta \,\,H\,\, = \,\, - \,149\,\,KJ\)
\(\,6.8\,\,gm\,\,N{H_3}\,\) ના ફેરફાર જોતાં \(\Delta H\,\, = \,\, - \frac{{149}}{{17}}\,\, \times \,\,6.8\,\,KJ\)
\( = \,\, - 59.6\,\,KJ\,\,\,\,\,\,\,\,\,\,\,\Delta \,H\,\, = \,\, - \,\,59.6\,\,KJ\)