Maximum work can a gas do, if it is allow to expand isothermally against — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

The magnitude of work done by gas expansion is $W = \int P_{\text{ext}} dV$. The higher the external pressure ($P_{\text{ext}}$) the gas successfully expands against, the greater the work done. Maximum work is achieved reversibly when $P_{\text{ext}}$ is infinitesimally smaller than the gas's internal (high) pressure.