RE-NEET2026Chemistry-Thermodynamics
RE-NEET 2026 Chemistry Entropy and Enthalpy MCQ Question
Type: MCQ-numerical-Medium-Class 11
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
A
2000.0
B
333.0
C
11.1
D
2.0
Correct Answer
Option C
Detailed Explanation
At equilibrium, ΔG = 0, so ΔH = TΔS. Given ΔH = 666 kJ mol⁻¹ and T = 60 °C = 333 K, ΔS = ΔH/T = 666/333 = 2.0 kJ K⁻¹mol⁻¹.
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