Question

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

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

Answer 1

Answer: (B)

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

$\Delta G^o=-RT\ln K=\Delta H^o-T\Delta S^o$

$\ln K=\frac{\Delta S^o}{R}-\frac{\Delta H^o}{RT}$

Thus, a plot of $\ln K$ versus $1/T$ (abscissa) will be straight line with slope equal to $-\frac{\Delta H^o}{R}$ and intercept $\frac{\Delta S^o}{R}$.

Hence, option B is correct.