Questions: Ozonolysis and Oxidative Cleavage of Alkenes
4 questions to test your understanding
Score: 0 / 4
Question 1 Multiple Choice
What are the products of treating 2-methylbut-2-ene with O₃, then (CH₃)₂S?
ATwo molecules of acetone
BAcetone and acetaldehyde
CAcetone and acetic acid
D2-Methylbutane-2,3-diol
Cutting (CH₃)₂C=CHCH₃ and capping each carbon with oxygen gives (CH₃)₂C=O, acetone, and CH₃CHO, acetaldehyde. Dimethyl sulfide is a reductive workup, so the aldehyde survives.
Question 2 Multiple Choice
What single product forms when cyclohexene is treated with O₃, then Zn in acetic acid?
ACyclohexanone
BHexanedial
CHexanedioic acid
DTwo molecules of propanal
The ring opens at the double bond, and both former alkene carbons, each bearing H, become aldehyde groups. The product is the six-carbon dialdehyde hexanedial. An oxidative workup would give hexanedioic (adipic) acid.
Question 3 True / False
In an oxidative ozonolysis workup with H₂O₂, aldehyde fragments become carboxylic acids, but ketone fragments are unchanged.
TTrue
FFalse
Answer: True
Hydrogen peroxide oxidizes the C–H bond of an aldehyde to give a carboxylic acid. A ketone carbon has no hydrogen to oxidize, so it stays a ketone.
Question 4 Short Answer
An alkene with formula C₆H₁₂ gives only acetone on ozonolysis with reductive workup. What is its structure?
Think about your answer, then reveal below.
Model answer: 2,3-Dimethylbut-2-ene, (CH₃)₂C=C(CH₃)₂.
Two molecules of acetone account for all six carbons. Joining their carbonyl carbons with a double bond gives a symmetrical tetrasubstituted alkene.