Question

Ozonolysis of 2,3-dimethyl but-2-ene, followed by decomposition by Zn dust and water gives _______.

• A. acetaldehyde
• B. propionaldehyde and acetone
• C. acetone
• D. acetaldehyde and butyraldehyde

Answer 1

The Correct Option is C

The given compound is 2,3-dimethylbut-2-ene, which has the structure:

CH₃–C(CH₃)=C(CH₃)–CH₃

It is a symmetrical alkene (both sides of the double bond have identical groups).

When ozonolysis occurs, the C=C double bond is cleaved, and each of the doubly bonded carbons is converted into a carbonyl group (C=O).

The reaction can be represented as:

CH₃–C(CH₃)=C(CH₃)–CH₃ ⟶ (i) O₃ ⟶ (ii) Zn / H₂O ⟶ 2 CH₃–CO–CH₃

The product formed is acetone (propanone).

Therefore, the overall reaction gives: \[ 2,3\text{-dimethylbut-2-ene} \xrightarrow[\text{Zn/H}_2\text{O}]{\text{O}_3} 2\, \text{acetone} \]