Question

what is the stretching frequency (in cm⁻¹) of the following carbonyl?

o
|
cl

1800
1745
1685
none of the above

Explanation:

Step1: Identify the carbonyl type

The given compound is an acyl - chloride with an aromatic ring attached to the carbonyl - containing carbon.

Step2: Recall carbonyl stretching frequency range

Acyl - chlorides have carbonyl stretching frequencies in the range of 1770 - 1815 $cm^{-1}$. The presence of the aromatic ring slightly lowers this value.

Answer:

1800