Question

A mixture of benzoic acid and naphthalene was dissolved in tert-butyl methyl ether and the resulting solution was extracted with aqueous sodium bicarbonate. The lower layer was separated and to it was added concentrated hydrochloric acid, upon which a white precipitate formed. What was the structure of the precipitate?

Answer 1

C₆H₅COOH Benzoic Acid

Step-by-step explanation:

Here we are using the extraction method to separate benzoic acid from naphtalene in the ether solution by reacting it with the base sodium bicarbonate to produce the salt sodium benzoate ( naphtalene remains in the organic layer ) .

The sodium benzoate is completely soluble in the aqueous layer being a salt, and reacts with hydrochloric acid ( again an acid base reaction ) which precipitates the benzoic acid since the it is insoluble in water hence separating it.