Question

Which is stronger, the C=O bond in an ester () or the C=O bond in a saturated ketone ()? Explain

Short answer

An ester C=O bondis stronger than a saturated ketone C=O bond.

Step-by-step solution

Energy

Energy is directly related to frequency and inversely related to wavelength. But in the case of wavenumber, energy is directly related to wavenumber.

Fundamentals to decide stronger bond

As the wavenumber increases, the energy needed to cause IR absorption increases, indicating greater bond strength.

Strength of ester and saturated ketone

The ester stretch occurs at higher wavenumbers and, therefore, higher energies. Since more energy is required to stretch that bond, the ester bond must be stronger.

Thus, an ester C=O bondis stronger than a saturated ketone C=O bond,respectively.