Correct order of carbonyl stretching frequency is(1 Ponto)acetone > formaldehyde >ethanoyl chloride > acetaldehydeethanoyl chloride> formaldehyde > acetaldehyde > acetoneacetone < formaldehyde < ethanoyl chloride < acetaldehydeethanoylchloride< formaldehyde < acetaldehyde < acetone

The correct order of carbonyl stretching frequency is:

Ethanoyl chloride > Formaldehyde > Acetaldehyde > Acetone

This order is based on the fact that the carbonyl stretching frequency is influenced by the electron withdrawing effect of the groups attached to the carbonyl carbon. The more electron withdrawing the group, the higher the carbonyl stretching frequency.

Ethanoyl chloride has a chlorine atom, which is a strong electron withdrawing group, hence it has the highest carbonyl stretching frequency. Formaldehyde has hydrogen atoms attached to the carbonyl carbon, which are less electron withdrawing than chlorine but more than the other groups in acetaldehyde and acetone. Acetaldehyde has a methyl group, which is less electron withdrawing than hydrogen. Acetone has two methyl groups, which makes it the least electron withdrawing, hence it has the lowest carbonyl stretching frequency.