Question

Why are grignard reagents soluble in ether but not in benzene?

Answer 1

Grignard reagent and ether form a complex where Mg acts as a Lewis acid and ether acts as a Lewis base. This makes Grignard reagent soluble in ether.

Grignard reagents form coordination complexes with Ether but not benzene since the former has a lone pair of electrons but the later does not.


Hope this will prove helpful for you.

Answer 2

A Grignard reaction is one which involves the reaction of an aryl halide or an alkyl halide with magnesium metal to give an alkyl magnesium halide, in the presence of dry ether.

R - X + Mg → R - MgX

Diethyl ether is used as a good solvent in the formation of Grignard reagents because of two important reasons.

Ether is an aprotic solvent and the bond between R - Mg is highly polar. Ether has a lone pair of electrons, which benzene does not have.

Ether is a great solvating agent but benzene is not. So, the Grignard reagent can be formed only in a good solvent but not in a non-polar solvent.