Question

Explain why benzaldehyde is less reactive than cyclohexanecarbaldehyde towards nucleophilic attack.

Short answer

Benzaldehyde is less reactive because the partial charge on carbonyl carbon participates in resonance with the benzene ring and makes the compound stable and less reactive.

Step-by-step solution

Resonance

It involves the delocalization of the pi electrons. Due to this, the compound becomes stable and becomes less reactive.

Explanation

The given compounds are shown below

Given compounds

Oxygen is more electronegative than carbon, and it pulls charge density. This creates a partial positive charge on the carbon of the carbonyl group. The positive charge on carbon is involved in resonance with the benzene ring.

Due to this, it becomes more stable and less reactive towards the nucleophilic attack. This is not the condition in cyclohexanecarbaldehyde.