Q53 / 200 · NEET 2002 · Chemistry

$2 \mathrm{~moles}$ of the ideal gas at $27^{\circ} \mathrm{C}$ temperature is expanded reversibly from $2 \mathrm{~L}$ to $20 \mathrm{~L}$. Find the entropy change $\left(\mathrm{R}=2 \mathrm{cal} \mathrm{mol}^{-1}\right.$ $\left.\mathrm{K}^{-1}\right)$ :

  • A
    92.1
  • B
    0
  • C
    4
  • Correct answer
    D
    9.2

Solution

$\begin{aligned} & \Delta \mathrm{S}=2.303 \mathrm{n} \mathrm{R} \log _{10} \frac{\mathrm{V}_2}{\mathrm{~V}_1} \\ & =2.303 \times 2 \times 2 \times \log _{10} \frac{20}{2} \\ & =2.303 \times 2 \times 2 \times 1 \\ & =9.212 \mathrm{cal} \end{aligned}$

Hence, the correct answer is option: 'D'.

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