The thermodynamic law, PVY = constant, is not applicable in case of

Answer: Option B

Since $$P{V}^Y=$$   constant is valid only for reversible process but since as free expansion is irreversible because it is working on a cycle by taking heat from a single reservoir and producing net expansion work when considered reversible and thus violating Kelvin-planck statement when considered reversible hence we can conclude free expansion is an irreversible process. And hence $$P{V}^Y=$$   constant can’t be valid.