Question

Write a balanced equation for the reaction of benzoic acid with hydroxide ion. Why is it necessary to extract the ether layer with sodium hydroxide?

Answer 1

benzioc acid in its neutral form is non-polar. So you cannot separate it from ether (also non-polar). you want to make benzoic acid polar by deprotonating it so you can separate it from ether.

sodium bicarbonate is a weak base, so it would deprotonate the acidic hydrogen on benzoic acid and makes it polar. However, since sodium bicarbonate is a weak base, it does not deprotonate the benzoic acid very efficiently. To do that, you can you sodium hydroxide, which is a much stronger base and can deprotonoate benzoic acid almost completely. so sodium hydroxide is a better choice.