Question

Acetaldehyde undergoes aldol condensation but trimethyl acetaldehyde doesnot

Answer 1

because aldol condensation only possible when there is alpha hydrogen but trimethylacetaldehyde lack alpha hydrogen

Answer 2

Answer: Because it does not have any $\alpha$-hydrogen atoms.

Explanation:

When two molecules of aldehyde containing $\alpha$-hydrogen atoms undergo condensation in the presence of a base to produce $\beta$-hydroxy aldehyde known as aldol, the reaction is known as Aldol condensation reaction.

Acetaldehyde has a chemical formula of $CH_3CHO$, which contains $\alpha$-hydrogen atoms, but in trimethyl acetaldehyde, no $\alpha$-hydrogen atoms are present and hence, it cannot undergo aldol condensation reaction.