Question

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

• A. \( \Delta S^\circ / R \)
• B. \( R \)
• C. \( \Delta H^\circ / R \)
• D. \( R \times \Delta S^\circ \)

Hint:

The Van’t Hoff equation shows the relationship between the equilibrium constant and temperature, with the intercept related to enthalpy.

Answer 1

The Correct Option is C

Step 1: Van’t Hoff Equation.
According to the Van’t Hoff equation: \[ \ln K = -\frac{\Delta H^\circ}{R} \cdot \frac{1}{T} + \text{constant} \] The intercept on the ordinate axis corresponds to \( \frac{\Delta H^\circ}{R} \).
Step 2: Conclusion.
The correct answer is (C), \( \Delta H^\circ / R \).