Question

For which of the following compounds, the aldehyde to be more stable than its hydrate?

• A.
• B.
• C.
• D. None of the above

Answer 1

The correct option is A

The addition of water ​to an aldehyde or a ​ketone forms a hydrate. ​
Generally, simple aldehydes are hydrated to some extent while simple ketones are not.
The extent to which an aldehyde or a ketone is hydrated in an aqueous solution depends on the substituents attached to the carbonyl group.
Electron-donating and bulky groups decrease the percentage of hydrate present at equilibrium.
Meanwhile, electron-withdrawing and small groups increases the percentage of hydrate present at equilibrium.

Compound (b) have more bulky and electron donating group so it is more stable than its hydrate form.