The equilibrium: NH₄HS(s) ⇌ NH₃(g) + H₂S(g) is achieved at the equilibrium pressure of 'X' bar at T — Chemical Equilibrium Chemistry Question

💡 Solution & Explanation

For NH₄HS(s) ⇌ NH₃(g) + H₂S(g), P_NH₃ = X/2 and P_H₂S = X/2. K_p = (X/2) × (X/2) = X² / 4. The standard free energy change ΔG° = -RT ln K_p = -RT ln(X² / 4) = -RT [2 ln X - ln 4] = -RT [2 ln X - 2 ln 2] = -2RT(ln X - ln 2). Therefore, correct answer is C.