Question

Which pair of solvents would make good extraction systems?

diethyl ether and dichloromethane

acetone and diethyl ether

water and diethyl ether

water and ethanol

water and dichloromethane

Answer 1

Soln 1:

The solvent pair with greater difference in polarity will make a good extraction pair. The solvent polarity index for

Dichloromethane is 3.1,

Acetone is 5.1,

Diethyl ether is 2.8,

Water is 10.2

Water and diethyl ether has a higher difference in polarity. So it makes a good pair for extraction.

Next comes Water and dichloromethane.

Water and ethanol are miscible, so they cannot be used as a extraction pair.

Acetone and diethylether has only a very small difference in polarity. So it cannot be a good pair.

Soln 2:

When an organic substance has to be separated from aqueous extract Diethyl ether and Dichloromethane pair serves good, where highly polar substances get extracted with dichloromethane and less polar substances get extracted with diethyl ether.