Question

Convert toluene into benzene in 2 steps reaction.

Answer 1

Hint: Toluene is an organic aromatic compound having a methyl group present on the carbon atom on the benzene ring. First, oxidize the toluene with hot potassium manganate solution and then react it with sodium hydroxide or calcium oxide.

Complete answer:
Toluene is an organic aromatic compound in which the methyl group is present on one of the carbon atoms of the benzene ring. The formula of toluene is ${{C}_{6}}{{H}_{5}}C{{H}_{3}}$. The structure of the toluene is given below:

Benzene is an aromatic ring of six carbon atoms having three double bonds. The formula of benzene is ${{C}_{6}}{{H}_{6}}$. The structure of the benzene is given below:

For converting the toluene to benzene in 2 steps, first, convert toluene to benzoic acid and then convert this benzoic acid to benzene.
When toluene is oxidized with hot potassium manganate solution and potassium hydroxide at 373 – 383 K, there is the formation of benzoic acid. Benzoic acid is an organic aromatic compound in which the carbon atom of the benzene ring is attached with the $-COOH$ group. The formula of benzoic acid is ${{C}_{6}}{{H}_{5}}COOH$. The reaction is given below:

Now, this benzoic acid can be converted into benzene, when the benzoic acid is heated with sodium hydroxide or calcium oxide. The reaction is given below:
 

So by these two steps, toluene can be converted into benzene.

Note:
When the aromatic compounds having methyl group on the carbon atoms of the benzene ring is oxidized with hot potassium manganate solution, all the methyl groups convert into the acid group, even there is more than one methyl is present on the benzene ring.