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Question #44834

Difficulty: 8/10 | 🟢 Free

The Question

A gaseous reactant \ce{A(g)} is continuously bubbled into an ideal solvent at a constant partial pressure of 1 bar1\text{ bar}. The dissolved gas undergoes a second-order dimerization reaction: \ce2A(aq)−>[k]A2(aq)\ce{2A(aq) ->[k] A2(aq)} The temperature coefficient of the intrinsic rate constant kk for a 10 K10\text{ K} rise from 300 K300\text{ K} to 310 K310\text{ K} is exactly 3.03.0. The standard enthalpy of dissolution of \ce{A(g)} in the solvent is ΔHsol∘=−42.47 kJ mol−1\Delta H^\circ_{\text{sol}} = -42.47\text{ kJ mol}^{-1}. Assuming both the activation energy (EaE_a) and enthalpy of dissolution are temperature-independent, determine the observed temperature coefficient (μobs=r310r300\mu_{\text{obs}} = \frac{r_{310}}{r_{300}}) for the overall rate of formation of \ce{A2(aq)}. (Given: ln⁡3=1.0986\ln 3 = 1.0986, R=8.314 J K−1 mol−1R = 8.314\text{ J K}^{-1}\text{ mol}^{-1})

Options

  • A.

    1.01.0

  • B.

    3\sqrt{3}

  • C.

    3.03.0

  • D.

    9.09.0

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Exception_Exposure

Learn to identify edge cases and boundary exceptions that JEE examiners hide in math problems.

Concepts Behind This Question

Temperature Coefficient (Q10)|Henry’s Law Constant (Kh) Trends

Why This Question Is Tricky

Common Mistakes

This problem tests the interplay between Arrhenius kinetics and the thermodynamics of gas solubility (Henry's Law).

Students often blindly apply the temperature coefficient to the overall reaction, forgetting that the concentration of a dissolved gas decreases with temperature due to its exothermic dissolution (ΔHsol<0\Delta H_{\text{sol}} < 0).

Furthermore, the trap involves the stoichiometric coefficient in the rate law (second-order), which doubles the exponential contribution of the solubility term, perfectly canceling the intrinsic activation energy and creating a temperature-independent reaction rate (Eapp=0E_{\text{app}} = 0).

Quick Facts About This Question

Question Information

SubjectChemistry
ChapterChemical Kinetics - Class 12
ConceptTemperature Coefficient (Q10)
Difficulty8
Cognitive Load7
Target Solve Time160 sec
AccessFree