Question

The entropy change involved in the isothermal reversible expansion of 2 moles of an ideal gas from avolume of $10d{m}^3$ to a volume of 100 $d{m}^3$ at ${27}^{0}C$ is:

• A. 42.3 $J{K}^{-1}mo{l}^{-1}$
• B. 38.3 $J{K}^{-1}mo{l}^{-1}$
• C. 35.8 $J{K}^{-1}mo{l}^{-1}$
• D. 32.3 $J{K}^{-1}mo{l}^{-1}$

Answer 1

The correct option is B 38.3 $J{K}^{-1}mo{l}^{-1}$

Isothermal reversible expansion of $2$ moles of an ideal gas from a valence of ${10dm}^3$ at ${27}^{0}C$ is to a volume of $100{dm}^3$. The entropy change involved in the above process be $\Delta S$.

$\Delta S=nRln\frac{V_2}{V_1}$

$=\left(2.303\right)\left(2\right)\left(8.314\right)log\left(\frac{100}{10}\right)$

$=38.3J$ ${mol}^{-1}$ $K^{-1}$

thus, entropy change of reaction is $38.3J$ ${mol}^{-1}$ $K^{-1}$.

Hence, the correct option is $\text{B}$