If there is a reaction mixture in an organic solvent that contains an organic acid, an organic base, neutral organic compounds, and base containing impurities, what is in the aqueous layer after complete treatment with naoh(aq)?

Answer is: organic acid will be in aqueous layer after treatment with sodium hydroxide.
An organic base, neutral organic compounds and base containing impurities will not change polarity with reaction with sodium hydroxide (base) because they not react with bases. Organic acid reacts with sodium hydroxide and change polarity because releases proton and become salt that dissolves in water. Other molecules are dissolved in nonpolar organic layer.