Q20 / 180 · COMEDK 2026 (9 May Shift 2) · Chemistry
Identify the INCORRECT statement
- Correct answerAA process will always be spontaneous at all temperatures, if T$\Delta$S is positive
- BFor spontaneous process $([\Delta H_{system} - T\Delta S_{system}]) < 0$
- CAt 273K, for the transition Ice$(s) \longrightarrow$ Water $(l)$, $\Delta$G = 0
- DEntropy is an extensive property and state function
Solution
$\Delta G = \Delta H - T\Delta S$
For a process to be spontaneous at all temperatures, $\Delta G$ must be negative at all temperatures. This is possible only when $\Delta H < 0$ and $\Delta S > 0$. If $\Delta S > 0$ (meaning $T\Delta S$ is positive) but $\Delta H > 0$, the process will be non-spontaneous at low temperatures where $\Delta H > T\Delta S$. Thus, a positive $T\Delta S$ alone does not guarantee spontaneity at all temperatures.
For a spontaneous process at constant temperature and pressure, $\Delta G_{system} = \Delta H_{system} - T\Delta S_{system} < 0$.
At $273$ K, ice and water are in equilibrium, so $\Delta G = 0$.
Entropy is an extensive property as it depends on the mass of the system, and it is a state function as it depends only on the initial and final states.
Answer: A process will always be spontaneous at all temperatures, if T$\Delta$S is positive
For a process to be spontaneous at all temperatures, $\Delta G$ must be negative at all temperatures. This is possible only when $\Delta H < 0$ and $\Delta S > 0$. If $\Delta S > 0$ (meaning $T\Delta S$ is positive) but $\Delta H > 0$, the process will be non-spontaneous at low temperatures where $\Delta H > T\Delta S$. Thus, a positive $T\Delta S$ alone does not guarantee spontaneity at all temperatures.
For a spontaneous process at constant temperature and pressure, $\Delta G_{system} = \Delta H_{system} - T\Delta S_{system} < 0$.
At $273$ K, ice and water are in equilibrium, so $\Delta G = 0$.
Entropy is an extensive property as it depends on the mass of the system, and it is a state function as it depends only on the initial and final states.
Answer: A process will always be spontaneous at all temperatures, if T$\Delta$S is positive
Hence, the correct answer is option: 'A'.