Question

1. Investigation of the solubility of the unknown compound X in three different solvents gave the following results:

Water: insoluble, Hexane: slightly soluble, Dichloromethane: soluble at any temperature

Based on the results, which of the following could be the identity of X?

CH3OH, benzene, or benzoic acid

Following the "like dissolves like" rule, explain which type(s) of intermolecular forces make the compound you chose soluble in di chloromethane

Answer 1

compound X is benzoic acid.

Benzoic acid is quite polar compound.

Though water is also polar compound benzoic acid is having a big hydrophobic benzene ring which makes it insoluble in cold water. [ however benzoic acid is soluble in hot water,dipole-dipole ineractions]

hexane is a non-polar solvent thus the polar benzoic acid does not / slightly dissolves in hexane.

Dichloromethane is a very polar compound thus benzoic acid dissolves freely in dichloromethane at all temperatures.[dipole-dipole interactions].