Q82 / 200 · NEET 2024 · Chemistry

The work done during reversible isothermal expansion of one mole of hydrogen gas at $25^{\circ} \mathrm{C}$ from pressure of 20 atmosphere to 10 atmosphere is (Given $\mathrm{R}=2.0 \mathrm{cal} \mathrm{K}^{-1} \mathrm{~mol}^{-1}$ )

  • Correct answer
    A
    -413.14 calories
  • B
    413.14 calories
  • C
    100 calories
  • D
    0 calorie

Solution

$\begin{aligned} W_{\text {rev, iso }} & =-2.303 n R T \log \frac{P_i}{P_f} \\ & =-2.303 \times 1 \times 2 \times 298 \times \log 2 \\ & =-2.303 \times 1 \times 2 \times 298 \times 0.3 \\ & =-413.14 \text { calories }\end{aligned}$

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

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