Question

What will be formed after oxidation of secondary alcohol with chromic anhydride (CrO3)?

• A. Aldehyde
• B. Ketone
• C. Carboxylic acid
• D. Ester

Hint:

Chromic anhydride is a strong oxidizing agent that selectively oxidizes secondary alcohols to ketones without affecting aldehydes or carboxylic acids.

Answer 1

The Correct Option is B

To solve the problem, we need to determine the product formed when a secondary alcohol is oxidized with chromic anhydride (CrO\(_3\)).

1. Understanding Secondary Alcohols:
A secondary alcohol has the general structure R\(_1\)R\(_2\)CHOH, where R\(_1\) and R\(_2\) are alkyl groups, meaning the carbon bearing the -OH group is attached to two other carbons.

2. Identifying the Reagent:
Chromic anhydride (CrO\(_3\)) is a strong oxidizing agent, often used in acidic conditions (e.g., with H\(_2\)SO\(_4\)) to form chromic acid, a common reagent for alcohol oxidation. It can also be used in other forms, such as in the Jones oxidation (CrO\(_3\) in aqueous sulfuric acid and acetone).

3. Oxidation of Secondary Alcohol:
When a secondary alcohol is oxidized with a strong oxidizing agent like CrO\(_3\), the -OH group is converted to a carbonyl group (C=O). Since the carbon is attached to two other carbons, the product is a ketone (R\(_1\)R\(_2\)C=O). For example, if the secondary alcohol is 2-propanol (CH\(_3\)CH(OH)CH\(_3\)), oxidation with CrO\(_3\) yields acetone (CH\(_3\)COCH\(_3\)), a ketone.

4. Considering Reaction Conditions:
CrO\(_3\) in acidic conditions ensures complete oxidation. Secondary alcohols do not oxidize further to carboxylic acids (unlike primary alcohols), as there is no hydrogen on the carbonyl carbon to allow further oxidation to a carboxyl group.

Final Answer:
Oxidation of a secondary alcohol with chromic anhydride (CrO\(_3\)) forms a ketone.