Question

Why is there no alpha hydrogen in benzaldehyde?

Answer 1

Hint: A benzene ring which has an formyl substituent attached to it is known as Benzaldehyde.It’s one of the simplest aldehyde yet it’s very useful industrially

Complete answer:
Organic compounds which have formyl group ( $R - \mathop C\limits^{\mathop {||}\limits^O } - H$ )attached to them are termed as Aldehyde.A formal group attached to a benzene is termed as benzaldehyde.

The carbon atom which is adjacent to the functional group in the compound is termed as alpha( $\alpha $ )carbon and the hydrogen atom attached to the alpha carbon is termed as alpha hydrogen.
In case of benzaldehyde the alpha carbon atom has no hydrogen atoms attached hence there is no alpha hydrogen present in benzaldehyde.Due to the absence of alpha hydrogen it also cannot undergo aldol condensation.

Note:
Benzaldehyde is a colourless liquid and has an almond like odour.Due to this reason it is also used as a flavouring agent in the food industry.