JEE Advanced · 2008 · 13 Apr 2008 · Paper 1 · Chemical Thermodynamics

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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 a correct explanation for STATEMENT-1
(B)STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is NOT a correct explanation for STATEMENT-1
(C)STATEMENT-1 is True, STATEMENT-2 is False
(D)STATEMENT-1 is False, STATEMENT-2 is True✓ Correct

Answer: (D)

Solution

STATEMENT-1 is False: At equilibrium,

Δ G = 0

(the Gibbs energy change for the reaction under the given conditions is zero), but

Δ G^{\circ}

(the standard Gibbs energy change) is generally not zero.

Δ G^{\circ}

depends on the equilibrium constant:

Δ G^{\circ} = - R T ln K

.

STATEMENT-2 is True: Chemical reactions proceed spontaneously in the direction of decreasing Gibbs energy (negative

Δ G

) at constant temperature and pressure.

Therefore, Statement-1 is false while Statement-2 is true.

JEE Advanced · 2008 · 13 Apr 2008 · Paper 1 · Single correct option

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JEE Advanced · 2008 · 13 Apr 2008 · Paper 1 · Chemical Thermodynamics

Solution

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