Correct option is D
Introduction
The Gibbs free energy change (ΔᵣG°) is a thermodynamic quantity that determines the spontaneity, equilibrium position, and maximum useful work of a chemical reaction.
It links enthalpy, entropy, temperature, and the equilibrium constant, but not reaction kinetics.
Information Booster
This is false because ΔᵣG° is purely a thermodynamic quantity and carries no information about reaction rate (kinetics).
Free energy change tells us whether a reaction is feasible (spontaneous) and how far it will proceed toward equilibrium (via K = e^(−ΔᵣG°/RT)), but it says nothing about how fast the reaction occurs.
The rate of a reaction depends on the activation energy (Eₐ) and the reaction pathway/mechanism, governed by the Arrhenius equation (k = A·e^(−Eₐ/RT)), not by the thermodynamic free-energy difference between reactants and products.
A reaction can be highly spontaneous (large negative ΔᵣG°) yet extremely slow — the conversion of diamond to graphite is a classic example, thermodynamically favourable but kinetically negligible at room temperature.
Because ΔᵣG° cannot yield a rate, statement (d) is the incorrect one and thus the answer.
Additional knowledge
· Sign and magnitude of ΔᵣG° can predict spontaneity — Correct. A negative ΔᵣG° indicates a spontaneous (thermodynamically favourable) reaction, a positive value a non-spontaneous one, and zero indicates equilibrium; the magnitude reflects how far from equilibrium the system lies.
· ΔᵣG° can predict the useful work extractable — Correct. The Gibbs free energy change represents the maximum non-expansion (useful) work obtainable from a reaction at constant temperature and pressure, which is the basis of electrochemical cell work (ΔG° = −nFE°).
· K and ΔᵣG° can be estimated from ΔᵣH° and ΔᵣS° at any temperature — Correct. Using ΔᵣG° = ΔᵣH° − TΔᵣS° and ΔᵣG° = −RT ln K, one can compute both ΔᵣG° and the equilibrium constant K at any specified temperature from measured enthalpy and entropy values.
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