Question

The effect of temperature on the spontaneity of reactions are represented as:  Which of the following is correct?

• (B) and (D) only
• (A) and (D) only
• (B) and (C) only
• (A) and (C) only

Hint:

The spontaneity of a reaction depends on both the enthalpy and the entropy change, and the effect of temperature can either make a reaction spontaneous or non-spontaneous.

Answer 1

The Correct Option is C

The spontaneity of a reaction is determined by the Gibbs free energy \( \Delta G = \Delta H - T \Delta S \).
- For \( \Delta H > 0 \) and \( \Delta S <0 \), the reaction is non-spontaneous at any temperature.
- For \( \Delta H > 0 \) and \( \Delta S > 0 \), the reaction is spontaneous at low temperatures.
- For \( \Delta H <0 \) and \( \Delta S <0 \), the reaction is non-spontaneous at low temperatures.
- For \( \Delta H <0 \) and \( \Delta S > 0 \), the reaction is spontaneous at any temperature. Thus, the correct answers are (B) and (C) only.