Concept:Ozonolysis cleaves a \( \text{C}=\text{C} \) double bond, placing a \( \text{C}=\text{O} \) double bond on each resulting fragment. To yield only
one type of aldehyde, the alkene must be perfectly symmetrical and have exactly one hydrogen on each double-bonded carbon.
Solution:- A. 1-Pentene (\( \text{CH}_2=\text{CHCH}_2\text{CH}_2\text{CH}_3 \)): Asymmetrical. Yields formaldehyde and butanal (two different aldehydes).
- B. 2-Methylpropene (\( (\text{CH}_3)_2\text{C}=\text{CH}_2 \)): Yields acetone (a ketone) and formaldehyde.
- D. 2,3-Dimethyl-2-butene (\( (\text{CH}_3)_2\text{C}=\text{C}(\text{CH}_3)_2 \)): Symmetrical, but yields two molecules of acetone (a ketone, no aldehydes).
- C. 2-Butene (\( \text{CH}_3\text{CH}=\text{CHCH}_3 \)): Symmetrical. Cleavage exactly in the middle yields two identical molecules of acetaldehyde (\( \text{CH}_3\text{CHO} \)). This is the only option that produces exactly one type of aldehyde.
Why other options are incorrect:- They either produce a mixture of different compounds, or they produce ketones rather than aldehydes.
Quality & Fidelity Assurance:
Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.