Molar heat capacity of a gas at constant temperature and pressure is:

Molar heat capacity$={\left(\frac{\partial \mathrm{H}}{\partial \mathrm{T}}\right)}_{\mathrm{P}}$

if $\partial \mathrm{T}=0$ at constant temperature.

Molar heat capacity$={\left(\frac{\partial \mathrm{H}}{0}\right)}_{\mathrm{P}}$

Molar heat capacity =$\infty$ .