Question

A plot of In K against $\frac{1}{T}$ (abscissa) is expected to be a straight line with intercept on ordinate axis equal to?

• A. $\frac{\Delta S^{\circ }}{2.303R}$
• B. $\frac{\Delta S^{\circ }}{R}$
• C. $-\frac{\Delta S^{\circ }}{R}$
• D. $R\times \Delta S^{\circ }$

Answer 1

The correct option is B

$\frac{\Delta S^{\circ }}{R}$

RT In $K=-\Delta G^{\circ }=T\Delta S^{\circ }-\Delta H^{\circ }$;
In $K=\frac{\Delta S^{\circ }}{R}-\frac{\Delta H^{\circ }}{RT}$
Thus, a plot of In K versus $\frac{1}{T}$ (abscissa) will be straight line with slope equal to $\frac{-\Delta H^{\circ }}{R}$ and intercept $\frac{\Delta S^{\circ }}{R}$.