$3 HC \equiv CH _{( g )} \rightleftharpoons C _{6} H _{6(\ell)}$
[આપેલ : $\Delta_{f} G ^{\circ}( HC \equiv CH )=-2.04 \times 10^{5}\, J mol ^{-1}$
$\Delta_{f} G ^{\circ}\left( C _{6} H _{6}\right)=-1.24 \times 10^{5}\, J mol ^{-1} ; R =8.314\,\left. J K ^{-1} mol ^{-1}\right]$
(Given ${\Delta _{fus}}H = 6\, kJ\, mol^{-1}$ at $0\,^oC$,
$C_p(H_2O, l) =75.3\, J\, mol^{-1} \, K^{-1}$ ,
$C_p(H_2O, s) = 36.8\, J\, mol^{-1} \, K^{ -1}$ )
$(I)$ ${H_2}(g) + \frac{1}{2}{O_2}(g) \to {H_2}O(l);$
$\Delta {H^o_{298\,K}} = - 285.9\,kJ\,mo{l^{ - 1}}$
$(II)$ ${H_2}(g) + \frac{1}{2}{O_2}(g) \to {H_2}O(g);$
$\Delta {H^o_{298\,K}} = - 241.8\,kJ\,mo{l^{ - 1}}$
તો પાણીની મોલર બાષ્પાયન એન્થાલ્પી .....$kJ\,mol^{-1}$