Question

Which of the following correctly represents the change in Gibbs free energy (ΔG) for a spontaneous process?

• A. \( \Delta G = 0 \)
• B. \( \Delta G < 0 \)
• C. \( \Delta G > 0 \)
• D. \( \Delta G = \Delta H - T\Delta S \)

Hint:

A negative \( \Delta G \) indicates that a process is spontaneous, and it depends on both the enthalpy change and the entropy change.

Answer 1

The Correct Option is D

The change in Gibbs free energy \( \Delta G \) is given by the equation: \[ \Delta G = \Delta H - T\Delta S, \] where:
- \( \Delta G \) is the change in Gibbs free energy,
- \( \Delta H \) is the change in enthalpy,
- \( \Delta S \) is the change in entropy,
- \( T \) is the absolute temperature in Kelvin.
For a process to be spontaneous, \( \Delta G \) must be negative. The equation shows that if the enthalpy decreases (exothermic reaction) and/or the entropy increases, the process will tend to be spontaneous. This equation is fundamental in determining the spontaneity of chemical reactions and processes.