Which of the following reactions with chloroform will give chloretone ?

A. HNO3

B. (CH3)2C = O

C. Chloral

D. (CH3)2CHCHO

To determine which reaction with chloroform will yield chloretone, we need to consider the chemical structure and reactivity of chloroform (CHCl3) and the options provided. Chloretone, or 2-chloro-2-methylpropan-1-one, is typically synthesized through a specific reaction involving chloroform and a ketone or aldehyde. Let's analyze each option to find the correct answer.

Analyzing the Options

• A. HNO3: This is nitric acid, which is primarily an oxidizing agent. It does not react with chloroform to produce chloretone.
• B. (CH3)2C = O: This represents acetone, a ketone. Chloroform can react with acetone in the presence of a base to form chloretone through a reaction known as the haloform reaction. This is a strong candidate.
• C. Chloral: Chloral (CCl3CHO) is an aldehyde. While it can react with chloroform, it does not lead to the formation of chloretone.
• D. (CH3)2CHCHO: This is isovaleraldehyde. While it can react with chloroform, it does not produce chloretone either.

Identifying the Correct Reaction

The most promising option here is B, acetone. The reaction between chloroform and acetone in the presence of a base (like sodium hydroxide) leads to the formation of chloretone. This occurs through a series of steps where the chloroform acts as a source of chlorine, and the acetone provides the carbon skeleton necessary for the chloretone structure.

Mechanism of the Reaction

In the presence of a base, chloroform can be deprotonated to form a trichloromethyl anion. This anion can then attack the carbonyl carbon of acetone, leading to the formation of an intermediate. Subsequent steps involve the elimination of chloride ions and rearrangement to yield chloretone.

Conclusion

Thus, the reaction that will give chloretone when combined with chloroform is option B, (CH3)2C = O (acetone). This reaction exemplifies how specific functional groups can interact to form new compounds, showcasing the versatility of organic chemistry.