Chemistry - Hydrocarbon Question with Solution | TestHub

Question Explanation:

The question asks for the major product when the given alkene is treated with cold alkaline dilute

KMnO₄ , which performs mild oxidation.

Concept:

Baeyer Test, Vicinal Diol Formation, Syn Addition, Alkene Oxidation.

Solution:

Cold, dilute alkaline KMnO₄ oxidizes alkenes to vicinal glycols (1,2-diols) by syn addition of two –OH

groups across the double bond.

Key points:

• Reaction is mild → no cleavage of C=C bond

• Addition of –OH groups occurs from the same side (syn addition)

• Product is a cis-diol

In the given substituted cyclohexene, syn addition leads to both –OH groups added on the same face of the ring, matching the stereochemistry shown in Option 3.

• Option 1 & 4: Incorrect stereochemistry

• Option 2: Shows oxidative cleavage, which occurs only under hot, concentrated KMnO₄

Final Answer: Option (C)