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Hydrocarbons

Short Answer Type

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

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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.

Mechanism of chlorination of benzene: Benzene on treatment with chlorine in the presence of halogen carrier (Fe or FeCl₃) forms chlorobenzene.

Different steps involved in the mechanism are:
(i) Generation of an electrophile (Cl⁺): The catalyst Lewis acid (FeCl₃) helps in the generation of an electrophile (Cl⁺) by causing polarisation of the chlorine molecule.

(ii) Formation of the carbocation: The electrophile (Cl⁺) attacks the benzene ring to form an intermediate carbocation which is resonance stabilised. It is a slow step.

Resonance hybrid of the above resonating structures can be represented as,

(iii) Proton transfer from the carbocation to form chlorobenzene.

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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.