Question

Rank the following compounds from highest wavenumber to lowest wavenumber for their C=O absorption band:

Short answer

The order followed as:

Step-by-step solution

Wavenumber of carbonyl

Wavenumber of carbonyl is defined as the stretching frequency of the bond and showing absorption in presence of the different functional groups in the IR region of 1760-1655$c{m}^{-}$

Wavenumber order of given carbonyl

Wavenumber of the molecule varies with a substituent of the carbonyl group as the group is having electron-withdrawing leads to an increase the wavenumber of stretching frequency and the electron donation group decrease the wavenumber so as per the given carbonyl H is electron-withdrawing is having highest wavenumber and carbonyl with two substituted methyl group have low wavenumber order as follow: