The total number of compounds from below when treated with hot KMnO4 giving benzoic acid is:
Show Hint
When using hot KMnO4, remember that it will oxidize alkyl groups on aromatic rings to carboxylic acids, making it useful for converting side chains into carboxyl groups.
Oxidative cleavage of organic compounds occurs upon reaction with hot potassium permanganate (KMnO4). Aromatic hydrocarbons featuring side chains, if possessing at least one benzylic hydrogen, convert to benzoic acid upon oxidation. The mechanism is as follows:
Treatment of an alkyl benzene derivative with hot KMnO4 oxidizes the side chain to a carboxyl group (-COOH), yielding benzoic acid, provided hydrocarbon chains with benzylic hydrogens (C-H bonds adjacent to the benzene ring) are present.
From the provided options, we identify compounds that yield benzoic acid when reacted with hot KMnO4:
1. Toluene or any compound with alkyl groups (methyl, ethyl, etc.) directly attached to the benzene ring. 2. Xylene (symmetrical with alkyl groups at different positions), if at least one alkyl group contains a benzylic hydrogen. 3. Compounds already in the form of benzoic acid will not be further converted under these conditions.
Therefore, only compounds from the figure that possess alkyl groups directly bonded to the benzene ring and contain benzylic hydrogens will produce benzoic acid upon reaction with hot KMnO4.
In summary, the total count of compounds yielding benzoic acid when treated with hot KMnO4 is 5.
