$\Delta H=30 \mathrm{kJ} / \mathrm{mol}$
$\Delta S=105 J K^{-1} \mathrm{mol}^{-1}$
For at equilibrium $\Delta G=0$
$\therefore \Delta G=\Delta H-T \Delta S$
$\Delta H=T \Delta S$
$T=\frac{\Delta H}{\Delta S}=\frac{30 \times 1000 J \mathrm{mol}-1}{105 \mathrm{JK}^{-1} \mathrm{mol}^{-1}}=285.7 \mathrm{K}$
$N{H_{3(g)}}\, + \,\,\frac{3}{2}\,Cu{O_{(s)}}\, \to \,\,\frac{1}{2}\,{N_{2(g)}}\, + \,\,\frac{3}{2}{H_2}{O_{(\ell )}}\, + \,\,\frac{3}{2}\,C{u_{(s)}}.$ ......$J$