Chemistry – Analytical techniques | e-Consult

Compound A: The reaction with acidified potassium dichromate (K₂Cr₂O₇) to give a green solution indicates the presence of a primary alcohol. Acidified dichromate is a mild oxidizing agent. Primary alcohols are oxidized to aldehydes, which are then further oxidized to carboxylic acids. The green colour arises from the formation of Cr³⁺ in the acidic conditions, which is characteristic of the oxidation of primary alcohols.

Possible structure of Compound A: CH₃CH₂CH₂OH (1-propanol)

Compound B: The reaction with Tollens' reagent to give a silver mirror indicates the presence of an aldehyde. Tollens' reagent is a test for aldehydes, as explained in the first question. The aldehyde group is reduced by the silver ions to form metallic silver.

Possible structure of Compound B: CH₃CHO (acetaldehyde)