Q98 · CSIR NET Chemistry, December 2016
Paper: CSIR NET December 2016 · Subject: Physical Chemistry · Chapter: Molecular Spectroscopy · Topic: Molecular Spectroscopy – General · Marks: 2 · Difficulty: Medium
The rotational constant and the fundamental vibrational frequency of $\mathrm{HBr}$ are, respectively, $10\,\mathrm{cm^{-1}}$ and $2000\,\mathrm{cm^{-1}}$. The corresponding values for $\mathrm{DBr}$ approximately are
(a)$20\,\mathrm{cm^{-1}}$ and $2000\,\mathrm{cm^{-1}}$
(b)$10\,\mathrm{cm^{-1}}$ and $1410\,\mathrm{cm^{-1}}$
(c)$5\,\mathrm{cm^{-1}}$ and $2000\,\mathrm{cm^{-1}}$
(d)$5\,\mathrm{cm^{-1}}$ and $1410\,\mathrm{cm^{-1}}$
Answer
Answer: D ✓ checked by 4AB · confidence high
Explanation
DBr: B ≈ 5 cm⁻¹, ν ≈ 1410 cm⁻¹ (d).
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