Question

One mole of an ideal gas at $300K$ is expanded isothermally from an initial volume of $1$ litre to $10$ litres. Then $\Delta S$ ($cal$ ${deg}^{-1}$ ${mol}^{-1}$) for this process is : ($R=2cal$ $K^{-1}$ ${mol}^{-1}$)

• A. $7.12$
• B. $8.314$
• C. $4.6$
• D. $3.95$

Answer 1

Answer: (C)

$4.6$

For an isothermal process
$\Delta S=2.303nR\log \frac{V_2}{V_1}$
$=2.303\times 1\times 2\log \frac{10}{1}$
$=4.6cal{deg}^{-1}{mol}^{-1}$