QJEEAdv08Ch0bf9: JEE Advanced 2008 Chemistry - Class 11 JEEAdv08Ch0bf9 Solution: Statement 1 : For every chemical reaction at equilibrium,…

Question

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Statement 1 : For every chemical reaction at equilibrium, standard Gibbs energy of reaction is zero.

and

Statement 2 : At constant temperature and pressure, chemical reactions are spontaneous in the direction of decreasing Gibbs energy.

A Statement 1 is True, Statement 2 is True; Statement 2 is correct explanation for Statement 1.
B Statement 1 is True, Statement 2 is True; Statement 2 is NOT correct explanation for Statement 1.
C Statement 1 is True, Statement 2 is False.
D Statement 1 is False, Statement 2 is True.

Accepted Answer

The Gibbs free energy varies from standard value as a function of temperature and equilibrium constant.

$\Delta$ G = $\Delta$ G $^\circ$ + RT ln K $_{eq}$

The standard Gibbs energy for a reaction is given by $\Delta$ G $^\circ$ .

At equilibrium, $\Delta$ G = 0whereas $\Delta$ G $^\circ$ for a reaction may or may not be zero.

$\Delta$ G $^\circ$ = $-$ RT ln K $_{eq}$

For a spontaneous process, Gibbs energy for a reaction is always negative, $\Delta$ G < 0.

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