Question

question 17
what is the stretching frequency (in cm^-1) of the following carbonyl?
1685
1715
1745

Explanation:

Step1: Identify carbonyl type

The given carbonyl is a cyclic ketone (cyclopentanone). Cyclic ketones have characteristic IR - stretching frequencies.

Step2: Recall frequency range

For five - membered cyclic ketones, the carbonyl stretching frequency is around 1745 cm⁻¹ due to ring strain increasing the force constant of the C=O bond.

Answer:

1745