Question

Which of the following equations are correct?
(A) U =H−PV
(B) G =H−TS
(C) U =q+W

• A. A, B and C
• B. A and B only
• C. A and C only
• D. B and C only

Hint:

Know the correct thermodynamic identities: \( G = H - TS \), \( H = U + PV \), \( \Delta U = q + W \).

Answer 1

The Correct Option is B

Let’s analyze the options: - (A) \( U = H - PV \): Incorrect Correct relation: \( H = U + PV \Rightarrow U = H - PV \) is not standard.
- (B) \( G = H - TS \): Correct, standard definition of Gibbs free energy.
- (C) \( U = q + W \): Incorrect in general; the first law of thermodynamics is: \[ \Delta U = q + W \] Only valid for change in internal energy, not \( U = q + W \).
Hence, only (A) and (B) are correct in context of standard thermodynamic identities.