In the IR spectrum of p-nitrophenyl acetate, the carbonyl absorption band appears at · ABC26OR0955
Subject: Organic Chemistry · Chapter: Organic Spectroscopy · Topic: IR · Exam: CSIR NET DEC 2012 · Marks: 2 · Difficulty: Easy
In the IR spectrum of p-nitrophenyl acetate, the carbonyl absorption band appears at
(a)$\mathrm{1670 ~ cm}^{-\mathrm{1}}$
(b)$\mathrm{1700 ~ cm}^{-\mathrm{1}}$
(c)$\mathrm{1730 ~ cm}^{-\mathrm{1}}$
(d)$1760 \mathrm{cm}^{-1}$.
Answer
Answer: D ✓ checked by 4AB · confidence high
Explanation
Phenyl esters absorb near 1760–1770 cm⁻¹ (the aryl-O lone pair is delocalised into the ring, so the C=O is stiffer than an alkyl ester at 1740), and the p-NO₂ group pushes it further up: ≈1760 cm⁻¹.