(A) U=H−pV, (B) G=H−TS, (C) U=q+W The enthalpy of system is sum of internal energy and product of pressure and volume. ∆H=∆U+p∆V;H=U+pV U=H−pV Also, ∆G=∆H−T∆S or G=H−TS According to first law of thermodynamics, ∆U=q−W ∴ Equation (C), U=q+W is incorrect. Option (b), only (A) and (B) are correct.
