Q31 / 120 · VITEEE 2016 · Chemistry

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

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

Solution

$\begin{array}{l} R T \ln K=-\Delta G^{\circ}=T \Delta S^{\circ}-\Delta H^{\circ} \\ \ln K=\frac{\Delta S^{\circ}}{R}-\frac{\Delta H^{\circ}}{R T} \end{array}$ Thus, a plot of $\ln K$ versus $1 / T$ (abscissa) will be straight line with slope equal to $\frac{-\Delta H^{\circ}}{R}$ and intercept $\frac{\Delta S^{\circ}}{R}$

Hence, the correct answer is option: 'B'.

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