RE-NEET 2026 Chemistry Entropy and Enthalpy MCQ Question
A protein undergoes reversible thermal denaturation from its initial state N to denatured state D according to N ⇌ D. At 60 °C, the concentrations of both N and D are equal at equilibrium, and the standard enthalpy change of denaturation is 666 kJ mol⁻¹. The standard entropy change (ΔS° in kJ K⁻¹mol⁻¹) of the protein upon denaturation at 60 °C is closest to
2000.0
333.0
11.1
2.0
Correct Answer
Detailed Explanation
To find the standard entropy change (ΔS°) for the denaturation of the protein, we can use the Gibbs free energy equation at equilibrium:
At equilibrium, ΔG° = 0. Given that ΔH° = 666 kJ mol⁻¹ and T = 60 °C = 333 K, we can rearrange the equation:
Solving for ΔS° gives:
Thus, the correct answer is D. The other options are incorrect because they do not satisfy the relationship derived from the Gibbs free energy equation.
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