Question

Enthalpy of fusion of a liquid is $1.435kcalmo{l}^{-1}$ and molar entropy change is $5.26calmo{l}^{-1}{K}^{-1}$, hence melting point of liquid is

• A. ${100}^{\circ }C$
• B. $0^{\circ }C$
• C. $373K$
• D. $-{273}^{\circ }C$

Answer 1

The correct option is B $0^{\circ }C$

Given:
$△H_{fusion}=1.435kcalmo{l}^{-1}$
$=1435calmo{l}^{-1}$
$△S=5.26calmo{l}^{-1}{k}^{-1}$
we know:
$△S_{fusion}=\frac{△H_{fusion}}{T}T=\frac{△H_{fus}}{△S_{fus}}=\frac{1435}{5.26}=272.81K=(272.81-273{)}^{o}C\approx 0^{\circ }C$