Final answer:
To separate amide and carboxylic acid products in an extraction, the use of NaHCO₃(aq) is recommended because it reacts with carboxylic acids to form water-soluble salts, leaving the amide unreacted for separation.
Step-by-step explanation:
To separate the amide and carboxylic acid products of a reaction in an extraction using aqueous solutions, it's essential to understand the chemical properties of the substances involved. Among the listed options, NaHCO₃(aq) or sodium bicarbonate would be effective. Sodium bicarbonate reacts with carboxylic acids to form water-soluble salts and carbon dioxide, thus converting the carboxylic acid to its salt form which is soluble in the aqueous layer, while the amide remains unreacted and can be separated by extraction.
Options such as NaCl(aq) would not be reactive, CH₃CO₂H(aq) is acetic acid itself and would not assist in separation, and CH₃OH(aq) (methanol) would not selectively react with either compound to facilitate separation. Thus, use of NaHCO₃(aq) enables the separation by taking advantage of the acidic property of the carboxylic acid without affecting the amide.