Question

Ice -Water mass ratio is maintained as $1:1$ in a given system containing water in equilibrium with ice at constant pressure. If $C_P$ (ice) = $C_P$ (water) = 4.18 J $mo{l}^{-1}{K}^{-1}$ molar heat capacity of such a system is

• A. $Infinity$
• B. $Zero$
• C. $75.48J{K}^{-1}mo{l}^{-1}$
• D. $4.182J{K}^{-1}mo{l}^{-1}$

Answer 1

Answer: (A)

The molar heat capacity is the heat capacity per unit amount (SI unit: mole) of a pure substance, i.e., The amount of heat needed to increase the temperature of one mole of a substance by one degree is the molar heat capacity.

If some finite heat is supplied, the ice would melt to water due to latent heat of fusion, without any change in temperature. So the molar heat capacity, here, is $\frac{heatsupplied}{zero}=Infinity$.