Question

Most of the organic chlorides, bromides and iodides react with certain metals to give compounds containing carbon-metal bonds.

i) Give one example for such a compound.

ii) How will you prepare the above compound?

b) Write any two electrophilic substitution reactions of chlorobenzene.

Answer 1

i) Grignard reagent; CH₃MgCI (Methyl magnesium chloride)

ii) Grignard reagents are prepared by treating haloalkanes with magnesium metal in dry ether.

haloalkanes with magnesium metal in dry ether.

CH₃Cl+Mg  \(\overset{dry\,ether}{\longrightarrow}\) CH₃MgCl

b) Halogenation : When chlorobenzene is treated with chlorine in presence of anhydrous FeCl₃ a mixture of 1,4-Dichlorobenzene (major product) and 1.2-Dichlorobenzene is formed.

Nitration : When chlorobenzene is treated with nitrating mixture (mixture of conc.HNO and cone. H SO ) a mixture of 1-Chloro-4-nitrobenzene (major product) and 1-Chloro-2- nitrobenzene (minor product) is formed.