Q49 / 160 · JIPMER 2007 · Chemistry
A reaction occurs spontaneously if
- A$T \Delta S \lt \Delta H$ and both $\Delta H$ and $\Delta S$ are + ve
- Correct answerB$T \Delta S\gt\Delta H$ and both $\Delta H$ and $\Delta S$ are + ve
- C$T \Delta S=\Delta H$ and both $\Delta H$ and $\Delta S$ are + ve
- D$T \Delta S\gt\Delta H$ and $\Delta H$ is + ve and $\Delta S$ is - ve
Solution
The spontaneity of reaction is based upon the negative value of $\Delta G, \Delta G$ is based upon $T, \Delta S$ and $\Delta H$ according to following equation (Gibbs-Helmholtz equation)
$\Delta G=\Delta H-T \Delta S$
If the magnitude of $\Delta H-T \Delta S$ is negative, then the reaction is spontaneous.
when $T \Delta S\gt\Delta H$ and $\Delta H$ and $\Delta S$ are + ve, then $\Delta G$ is negative.
Hence, the correct answer is option: 'B'.