Question

Which of the following alcohols is oxidized to a ketone by chromic acid?

• A. i
• B. ii
• C. iii
• D. iv
• E. v

Answer 1

The correct option is B ii

Secondary alcohols are easily oxidized without breaking carbon-carbon bonds only as far as the stage. No further oxidation is seen except under very stringent conditions. Tertiary alcohols cannot be oxidized at all without breaking carbon-carbon bonds, whereas primary alcohols can be oxidized to aldehydes or further oxidized to carboxylic acids.
Chromic acid ( generated by mixing sodium dichromate, with sulfuric acid) is an effective oxidizing agent for most alcohols. It is a strong oxidant, and it oxidizes the alcohol as far as possible without breaking carbon-carbon bonds. Chromic acid oxidizes primary alcohols to carboxylic acids, and it oxidizes secondary alcohols to ketones. Tertiary alcohols do not react with chromic acid under mild conditions. With a higher temperature or a more concentrated, carbon-carbon bonds may be oxidized; however, yields from such strong oxidations are usually poor.