Question

For a particular reaction $△H^0=-76.6KJ$ and $\Delta S^0=226J{K}^{-1}$. This reaction is:

• A. spontaneous at all temperatures
• B. non-spontaneous at all temperatures
• C. spontaneous at temperature below ${66}^0$C
• D. spontaneous at temperature above ${66}^0$C

Answer 1

The correct option is A spontaneous at all temperatures

Given: Change in enthalpy $△H^o=-76.6KJ$

Change in Entropy $△S^o=226J{K}^{-1}$

Using the relation, $△G=△H-T△S$

$△G=-76.6KJ-T\times 226J{K}^{-1}$

Since, both enthalpy $\left(△H^o\right)$ and Entropy term $\left(T△S^o\right)$ is negative. Hence $△G$ is negative whatever be the temperature.