Question

Benzaldehyde gives a positive test with tollens reagent but not with fehling's and benedict reagent

Answer 1

Fehlings solution and Benedict's is only for Aliphatic aldehydes, whereas benzaldehyde is an aromatic one. Hence no reaction.

Answer 2

Answer:

Detailed Explanation:

Benzaldehyde gives a positive test with Tollens reagent but not with Fehling and Benedict’s solution.

Because The electron donating resonance effect of the benzene ring increases the electron density in

the carbonyl group of benzaldehyde. Hence only stronger oxidizing agent can oxidise C-H to COOH to

form carboxylic acid but weaker reagent (like fehling, Benedict) fail to oxidise.