Alkenes
Ozonolysis of 2-butene followed by reductive workup (Zn/H₂O) gives:
Select the correct option:
Solution
Twomoleculesofethanal(acetaldehyde)
Ozonolysis cleaves the C=C double bond, and each carbon of the original double bond ends up as a carbonyl group. 2-Butene is CH₃–CH=CH–CH₃. The double bond is between C2 and C3. Cleavage gives: CH₃–CHO (ethanal) from C2 side and CH₃–CHO (ethanal) from C3 side. Since both fragments are identical, the product is two molecules of ethanal (CH₃CHO). Reductive workup (Zn/H₂O) ensures no further oxidation to carboxylic acids. The plausibility check: two carbons each bearing one methyl group and one H is consistent with ethanal.
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About This Question
- Subject
- chemistry
- Chapter
- hydrocarbons
- Topic
- alkenes
- Difficulty
- Medium
- Year
- 2025
Solution
Correct Answer:
Twomoleculesofethanal(acetaldehyde)
Ozonolysis cleaves the C=C double bond, and each carbon of the original double bond ends up as a carbonyl group. 2-Butene is CH₃–CH=CH–CH₃. The double bond is between C2 and C3. Cleavage gives: CH₃–CHO (ethanal) from C2 side and CH₃–CHO (ethanal) from C3 side. Since both fragments are identical, the product is two molecules of ethanal (CH₃CHO). Reductive workup (Zn/H₂O) ensures no further oxidation to carboxylic acids. The plausibility check: two carbons each bearing one methyl group and one H is consistent with ethanal.
This medium difficulty chemistry question is from the chapter hydrocarbons, covering the topic of alkenes. It appeared in the 2025 exam.
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