what is the stretching frequency (in cm⁻¹) of the following carbonyl?\nnone of the above\n1775\n1745\n1685
what is the stretching frequency (in cm⁻¹) of the following carbonyl?\nnone of the above\n1775\n1745\n1685
Answer
Explanation:
Step1: Identify the carbon - carbonyl type
The given compound is an $\alpha,\beta$-unsaturated ester.
Step2: Recall the IR stretching frequency range
For $\alpha,\beta$-unsaturated esters, the carbonyl stretching frequency is around $1680 - 1700\ cm^{-1}$ due to the conjugation of the carbonyl group with the double - bond which lowers the force constant and thus the stretching frequency.
Answer:
D. 1685