If θr denotes the characteristic temperatures of rotation, then the magnitude of [θr, (H₂). θr (D₂)] / [θr(H D)]² (assume the bond lengths to be the same for all the molecules) is:

(c) 8/9. Explanation: θr ∝ 1/μ: μ(H₂) = ½, μ(D₂) = 1, μ(HD) = ⅔ → (2 × 1)/(3/2)² = 8/9 (c).

Q25 · CSIR-NET Chemistry, December 2011

Paper: CSIR-NET December 2011 · Subject: Physical Chemistry · Chapter: Statistical Thermodynamics · Topic: Statistical Thermodynamics – General · Marks: 2 · Difficulty: Medium

If $\theta_{\mathrm{r}}$ denotes the characteristic temperatures of rotation, then the magnitude of $\left[\theta_{r},\left(H_{2}\right) . \theta_{r}\left(D_{2}\right)\right] /\left[\theta_{r}(H D)\right]^{2}$ (assume the bond lengths to be the same for all the molecules) is:

(a)2/3

(b)3/2

(c)8/9

(d)9/8

Answer

Answer: C ✓ checked by 4AB · confidence high

Explanation

θr ∝ 1/μ: μ(H₂) = ½, μ(D₂) = 1, μ(HD) = ⅔ → (2 × 1)/(3/2)² = 8/9 (c).

Study loop for Statistical Thermodynamics

1. Practise the PYQsPrevious-year questions, with answers

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