Question

A mix of sand, benzoic acid, and naphthalene in ether is best separated by:

A) filtration, followed by acidic extraction, followed by recrystallization

B) filtration, followed by basic extraction, followed by evaporation

Answer 1

Answer is B) filtration, followed by basic extraction, followed by evaporation

Mixtrue contains sand which will be separated by first filtration. Then, in basic extraction addition of base such as sodium bicarbonate solution will form salt of benzoic acid and thus this salt will be more solube in water rather than ether. Hence, benzoic acid salt will completely goes in to water solution leaving behind naphthalene in ether as naphthalene is a neutral compound and dosenot forms salt. Finally, naphthalene (only remaning substance from the mixture in ether) will be obtained evaporation of ether.