Under isothermal conditions, a gas at 300 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] (NEET 2019)

Expansion of a gas against a constant external pressure is an irreversible process. The work done in an irreversible process = – Pext ∆V = – Pext (V₂ – V₁) = –2 (0.25 – 0.1) = – 2 × 0.15 L bar = – 0.30 × 100 J = – 30 J THERMODYNAMICS AND THERMOCHEMISTRY 57