A student was attempting to extract benzoic acid from a diethyl ether solution. Aqueous hydrochloric acid was used to perform the extraction. When the aqueous layer was neutralized with sodium hydroxide, no precipitate of benzoic acid formed. What went wrong?

The separation technique of benzoic acid from diethyl ether is first the usage of the base and then acid.

As, benzoic acid is soluble in diethyl ether and on adding base, it forms sodium benzoate which is soluble in aqueous layer and thus separates from diethyl ether. Acid is then added to convert sodium benzoate in the aqueous layer back to benzoic acid.

But, in the given question, acid is added first and then base and this went wrong.