Question

which compound will give a positive result in a tollens test? more than one of the compounds will give a positive tollens test result.

Explanation:

Tollens' test is used to detect aldehydes. Aldehydes are oxidized by Tollens' reagent (ammoniacal silver nitrate) to carboxylic - acids, and silver ions are reduced to metallic silver. The first compound is an ester, the second is a ketone, the third is an aldehyde (benzaldehyde), and the fourth is an alkene with an aldehyde - like group (enal). The aldehyde (benzaldehyde) will give a positive Tollens' test result as it has a terminal carbonyl group with a hydrogen attached to the carbonyl carbon.

Answer:

C. The compound with the benzene ring and - CHO group (benzaldehyde)