Question

What is the name of the hydrocarbon that yields ethanal and propanone upon reductive ozonolysis?

• A. But-2-ene
• B. 2-Methylbut-2-ene
• C. 2-Methylbut-1-ene
• D. Pent-2-ene

Hint:

In ozonolysis problems, determine the alkene by combining the carbon fragments of the aldehydes or ketones formed after cleavage of the double bond.

Answer 1

The Correct Option is B

Concept: Ozonolysis is a reaction in which an alkene reacts with ozone to break the carbon–carbon double bond. The products formed depend on the substituents attached to the double-bonded carbon atoms. In reductive ozonolysis, the ozonide formed is reduced (usually using zinc and water or dimethyl sulfide), producing aldehydes or ketones.

Step 1: Identify the products given.
The products of the reaction are:
• Ethanal \((CH_3CHO)\)
• Propanone \((CH_3COCH_3)\)

Step 2: Reconstruct the original alkene.
Ethanal indicates that one carbon of the double bond had a methyl group and a hydrogen attached. Propanone indicates that the other carbon of the double bond had two methyl groups attached. Combining these fragments gives the alkene structure corresponding to 2-methylbut-2-ene. \[ CH_3CH=C(CH_3)_2 \]

Step 3: Conclusion.
Thus, the hydrocarbon that produces ethanal and propanone on reductive ozonolysis is 2-Methylbut-2-ene.