Which of the following will have the highest wave number for the carbonyl stretch in the IR spectrum?

Question

Quizplus · Accepted Answer

The molecule with the highest wave number for the carbonyl stretch in the IR spectrum will have the strongest bond, and therefore the highest frequency. This bond strength is determined by the electronegativity and size of the atoms bonded to the carbonyl carbon. In option A, the carbonyl carbon is bonded to two more electronegative atoms (oxygen) than the carbonyl carbons in options B, C, and D, which only have one oxygen atom bonded to the carbonyl carbon. The increased electron density around the carbonyl carbon in option A will result in a stronger C=O bond and a higher wave number in the IR spectrum.

Which of the Following Will Have the Highest Wave Number