Aromatic hydrocarbons of formula C8H10 that contain a benzene ring are oxidised with hot alkaline KMnO4 and then acidified. How many of the isomers give a benzene-dicarboxylic acid? Count constitutional isomers only (no stereoisomers).

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Aromatic hydrocarbons of formula $C X_{8} H X_{10}$ that contain a benzene ring are oxidised with hot alkaline $KMnO X_{4}$ and then acidified. How many of the isomers give a benzene-dicarboxylic acid? Count constitutional isomers only (no stereoisomers).

Answer: C

The isomers are ethylbenzene and the o-, m- and p-xylenes. Ethylbenzene has only one side chain and gives benzoic acid. Each xylene has two methyl groups, so each is oxidised to a benzenedicarboxylic acid (phthalic, isophthalic, terephthalic acid). The count is 3.

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Aromatic hydrocarbons of formula CX8​HX10​ that contain a benzene ring are oxidised with hot alkaline KMnOX4​ and then acidified. How many of the isomers give a benzene-dicarboxylic acid? Count constitutional isomers only (no stereoisomers).

Answer: C

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Aromatic hydrocarbons of formula $C X_{8} H X_{10}$ that contain a benzene ring are oxidised with hot alkaline $KMnO X_{4}$ and then acidified. How many of the isomers give a benzene-dicarboxylic acid? Count constitutional isomers only (no stereoisomers).