Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
COMEDK20269 May 2026Evening ShiftChemistryThermodynamics (C)Actual

Identify the INCORRECT statement

Options

  1. AA process will always be spontaneous at all temperatures, if T S is positive
  2. BFor spontaneous process ([ H_ system - T S_ system ]) < 0
  3. CAt 273K, for the transition Ice (s) Water (l) , G = 0
  4. DEntropy is an extensive property and state function

Correct answer

A. A process will always be spontaneous at all temperatures, if T S is positive

Step-by-step solution

G = H - T S For a process to be spontaneous at all temperatures, G must be negative at all temperatures. This is possible only when H 0 . If S > 0 (meaning T S is positive) but H > 0 , the process will be non-spontaneous at low temperatures where H > T S . Thus, a positive T S alone does not guarantee spontaneity at all temperatures. For a spontaneous process at constant temperature and pressure, G_ system = H_ system - T S_ system At 273 K, ice and water are in equilibrium, so G = 0 . Entropy is an extensive prope

Practice Thermodynamics (C) on Quantrex Academy →

More from Thermodynamics (C)

The standard enthalpies of formation of CH₄ (g), CO₂ (g) and H₂ O(l) are -74.8 kJ mol ⁻¹ , -393.5 kJ mol ⁻¹ and -285.8 kJ mol ⁻¹ respectively. Then the enthalpy change for the give 2026For an ideal gas undergoing an isothermal change, there is 2026Ozone is formed by the reaction O _ 2(g) + O _ (g) O _ 3(g) , H = -107.2 kJ . Given O=O bond energy is 498.0 kJ mol ⁻¹ , the average bond energy of ozone is: 2026H and S for a reaction are 35.5 kJ mol ⁻¹ and 83.6 J K ⁻¹ respectively. Assuming that H and S do not vary with temperature, the reaction is spontaneous when: 2026The heat of combustion of carbon to CO ₂ is -393.5 kJ mol ⁻¹ . The heat released on the formation of 35.2 g of CO ₂ by combustion of C is: 20265 moles of a gas is allowed to pass through a series of changes as shown in the graph, in a cyclic process. The processes C A , B C and A B respectively are 20251 mole of an ideal gas is allowed to expand isothermally and reversibly from 1 L to 5 L at 300 K. The change in enthalpy (in kJ ) is ( R =8.3 ~J ~K ⁻¹ ~mol ⁻¹ ) 2025Consider the following. Statement-I : Both internal energy (U) and work (w) are state functions. Statement-II : During the free expansion of an ideal gas into vacuum, the work done 2025 Full Thermodynamics (C) list All COMEDK PYQs