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Hydrocarbons

Short Answer Type

231. What happens when:
Toluene is heated with concentrated sulphuric acid.

461 Views

232. What happens when:
p-xylene is heated with alkaline KMnO₄.

300 Views

233.

What happens when:
Benzene is treated with n-propyl chloride in the presence of anhydrous AlCl₃.

532 Views

Long Answer Type

234.

Discuss the mechanism of electrophilic substitution reactions of benzene?

869 Views

235. Discuss the mechanism of chlorination of benzene.

341 Views

236.

How is benzene converted to nitrobenzene? Give mechanism.

161 Views

237.

How benzene is converted into benzene sulphonic acid? Give its mechanism.
Or
Explain the mechanism of sulphonation of benzene.

524 Views

238.

Discuss the mechanism of Friedel Craft’s reaction.
Or
Discuss the mechanism of Friedel Craft’s alkylation of benzene. Give the mechanism of reaction of benzene within the presence of AlCl_3.Or

How is benzene converted into aceto-phenone? Name the reaction and discuss the mechanism explaining each step.

Or

Give the mechanism of acylation of benzene.

228 Views

Short Answer Type

239.

Why does benzene undergo electrophilic substitution reactions easily and nucleophilic substitutions with difficulty?

588 Views

Long Answer Type

240.
Discuss the directive influence of substituents on disubstitution in benzene.

All the six hydrogen atoms of benzene are equivalent. Therefore, replacement of any one of these six hydrogen atoms by any substituent always gives a single monosubstituted benzene derivative. But in the case of disubstitution, three isomeric products are possible. These are ortho (o), meta (m) and para (p).

The position to be occupied by the second entering group depends on upon the nature of the group already present. This ability of a group already present in the benzene ring to direct the incoming group to a particular position is called the directive influence of groups. The groups have been classified into two types:

(i) Ortho and para directing groups: Such groups are directing the incoming group to attack at the ortho and para positions. For example,

In general, all electron donating groups are o, p-directing.

(ii) Meta directing groups. Such groups direct the incoming group to attack at the meta position. For example -NO₂, - CN, -CHO, -COR, -COOH, -SO₃H etc.