The rate of an acid-catalyzed reaction in aqueous solution follows the rate equation r=k [X⁺] [Y²⁻] [H⁺] If k₁₆ and k₄ are rate constants for the reaction at ionic strength of 16 mol L⁻¹ and 4 mol L⁻¹, respectively ln (k₄)/(k₁₆), in terms of Debye-Huckel constant (B=0.51), is

Q81 · CSIR-NET Chemistry, December 2016

Paper: CSIR-NET December 2016 · Subject: Physical Chemistry · Chapter: Chemical Kinetics · Topic: Rate Laws Order · Marks: 2 · Difficulty: Medium

The rate of an acid-catalyzed reaction in aqueous solution follows the rate equation

\[ \mathrm{r}=\mathrm{k}\left[\mathrm{X}^{+}\right]\left[\mathrm{Y}^{2-}\right]\left[\mathrm{H}^{+}\right] \]

If $\mathrm{k}_{16}$ and $\mathrm{k}_{4}$ are rate constants for the reaction at ionic strength of $16 \mathrm{mol} \mathrm{L}^{-1}$ and $4 \mathrm{mol} \mathrm{L}^{-1}$, respectively $\ln \frac{\mathrm{k}_{4}}{\mathrm{k}_{16}}$, in terms of Debye-Huckel constant $(\mathrm{B}=0.51)$, is

(a)4B

(b)8B

(c)10B

(d)12B

Answer

Answer: B ✓ checked by 4AB · confidence medium

The source book printed no answer; this one was worked out and checked — see the explanation.

Explanation

Brønsted–Bjerrum: log k = log k₀ + 2B z_A z_B √I with z_X z_Y = (+1)(−2) = −2. log(k₄/k₁₆) = 2B(−2)(√4 − √16) = 8B.

Study loop for Chemical Kinetics

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