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NEET levelSingle correct optionDifficulty 1 of 3ce121

A plot of $ln K$ against $1/ T$ for a reaction is a straight line. Its slope is

A $- Δ H^{\circ} / R$
B $+ Δ H^{\circ} / R$
C $- Δ S^{\circ} / R$
D $- Δ H^{\circ} / (2.303 R)$

Answer: A

Combining

Δ G^{\circ} = - RT ln K

with

Δ G^{\circ} = Δ H^{\circ} - T Δ S^{\circ}

gives

ln K = - \frac{Δ H ^{\circ}}{R} \frac{1}{T} + \frac{Δ S ^{\circ}}{R}

. The slope is

- Δ H^{\circ} / R

and the intercept is

Δ S^{\circ} / R

. The factor 2.303 appears only for a

lo g_{10} K

plot.

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