Question

Which of the following substrates, on oxidation with alkaline potassium permanganate followed by acid hydrolysis, will not give benzoic acid.
A. n-Butyl benzene
B. Isopropyl benzene
C. tert-Butyl benzene
D. Toluene

Answer 1

In organic chemistry, various reagents are used for various purposes. Potassium permanganate is a famous reagent that is used for the oxidation process. Acid hydrolysis is the process in which acid is used to catalyze the cleavage of the chemical bond via a nucleophilic substitution reaction, with the addition of water.

Complete step by step answer:
Potassium permanganate is amongst the most common oxidizing agents. It can be used to oxidize a wide range of compounds. The products of the reactions may vary but the final result is mostly a carboxylic acid due to the strong nature of potassium permanganate oxidation.
Alkylbenzene when treated with the potassium permanganate reagent leads to the oxidation of the compound to form benzoic acid.
The position directly adjacent to the aromatic group is called the benzylic position.
This reaction only works in the presence of hydrogen attached to the carbon.
In options (A) we see that it has a primary carbon chain with all carbon being of primary nature, while in option (B) we see that isopropyl benzene is a compound which has the maximum degree of carbon as secondary.
However tertiary butyl benzene has degree carbon and thus there is the absence of hydrogen attached to the carbon atom and thus this compound is unable to form benzoic acid upon oxidation with potassium permanganate.

So, the correct answer is Option C .

Note: Carbon is a tetravalent atom which means it has four valence electrons and thus can form four covalent bonds with atoms. Based on this property the carbon atom can be categorized as primary, secondary, or tertiary. The carbon which is attached to only one other carbon atom is called primary carbon, the carbon atom with the attachment of two other carbon atoms is secondary carbon whereas the carbon atom with the attachment of three carbon atoms is termed as a tertiary carbon atom.