Q18 · CSIR NET Chemistry, December 2013
Paper: CSIR NET December 2013 · Subject: Organic Chemistry · Chapter: Organic Spectroscopy · Topic: IR · Marks: 2 · Difficulty: Easy
In the IR spectrum of p-nitrophenyl acetate, the carbonyl absorption band appears at
(a)$1660\,\mathrm{cm}^{-1}$
(b)$1700\,\mathrm{cm}^{-1}$
(c)$1730\,\mathrm{cm}^{-1}$
(d)$1770 \mathrm{cm}^{-1}$
Answer
Answer: D ✓ checked by 4AB · confidence high
Explanation
An aryl acetate absorbs higher than a normal ester (1740 cm⁻¹) because the aryloxy oxygen is conjugated to the ring; the p-nitro group withdraws further. p-Nitrophenyl acetate: ≈ 1770 cm⁻¹.
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