Question

For the process:
$H_{2}O\left(l\right)\text{(1 bar, 373 K)}\rightleftharpoons H_{2}O\left(g\right)\text{(1 bar, 373 K)}$
the correct set of thermodynamic parameters is:

• A. $\Delta G>0,\Delta S=+ve$
• B. $\Delta G=0,\Delta S=+ve$
• C. $\Delta G=+ve,\Delta S=0$
• D. $\Delta G=-ve,\Delta S=+ve$

Answer 1

The correct option is B $\Delta G=0,\Delta S=+ve$

This is a phase transformation and hence, $\Delta G=0$. Since, $H_{2}O\left(l\right)$ is changing to $H_{2}O\left(g\right)$ at the same temperature and pressure, $\Delta S=+ve$.