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JEE Main · 2026 · 23 Jan 2026 · Shift 1 · General Organic Chemistry

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Consider all the structural isomers with molecular formula are separately treated with KOH (aq) to give respective substitution products, without any rearrangement. The number of products which can exhibit optical isomerism from these is ____ .

Answer: 3

Solution

There are eight structural isomers of , and aqueous KOH replaces bromine by hydroxyl at the same carbon without rearrangement, giving the corresponding pentanol in each case. An alcohol is optically active only when it contains a carbon bonded to four different groups. Among the products, pentan-2-ol, 2-methylbutan-1-ol and 3-methylbutan-2-ol each possess such a stereocentre, while pentan-1-ol, pentan-3-ol, 2-methylbutan-2-ol, 3-methylbutan-1-ol and 2,2-dimethylpropan-1-ol do not. The number of products that can exhibit optical isomerism is 3.

JEE Main · 2026 · 23 Jan 2026 · Shift 1 · Integer answer

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