Question

The reagent used in the conversion of alcohol into aldehyde is:

• A. $LiAlH_4$
• B. PCC
• C. $NaBH_4$
• D. Grignard reagent

Hint:

Think of PCC as a "controlled" stop. It stops the oxidation at the Aldehyde stage. Stronger reagents like Jones Reagent ($CrO_3/H_2SO_4$) are like an express train—they go all the way to the Carboxylic Acid!

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
To convert a primary alcohol into an aldehyde, we need an oxidizing agent. However, many strong oxidizing agents (like $KMnO_4$) will continue to oxidize the aldehyde into a carboxylic acid. Therefore, a "mild" or "selective" oxidizing agent is required.

Step 2: Detailed Explanation:

• PCC (Pyridinium Chlorochromate): This is a mild oxidizing agent. It selectively oxidizes primary alcohols to aldehydes and secondary alcohols to ketones without further oxidation to carboxylic acids.
• $LiAlH_4$ and $NaBH_4$: These are reducing agents, not oxidizing agents. They would do the opposite (convert an aldehyde back into an alcohol).
• Grignard reagent: This is used for carbon-carbon bond formation, not for the simple oxidation of an alcohol to an aldehyde.

Step 3: Final Answer:
The reagent used is PCC.