STANDARDChemistry-Thermodynamics

STANDARD Chemistry Work done by gases MCQ Question

Type: MCQ-numerical-Medium-Class 11

Under isothermal conditions, a gas at 30 K expands from 0.1 L to 0.25 L against a constant external pressure of 2 bar. The work done by the gas is [Given that 1 L bar = 100 J]

A

30 J

B

−30 J

C

5 kJ

D

25 kJ

Correct Answer

Option B

Detailed Explanation

Expansion of a gas against a constant external pressure is an irreversible process. The work done in an irreversible process is calculated as −Pₑₓₜ ΔV = −Pₑₓₜ (V₂ − V₁) = −2(0.25 − 0.1) = −2 × 0.15 L bar = −0.30 × 100 J = −30 J.

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