To isolate a basic organic compound from nonbasic compounds, which should you add?

The correct approach to isolate a basic organic compound from nonbasic compounds involves the addition of an acid to the solution containing the mixture. When an acid is introduced, it protonates the basic organic compound, converting it into its corresponding salt, which is more soluble in the aqueous layer. This phase separation allows for the basic compound to be extracted into the aqueous layer, while the nonbasic compounds remain in the organic layer.

This technique relies on the differing solubility properties of the protonated basic compound and the nonbasic compounds. By carefully controlling the pH through the addition of acid, the isolation can be effectively achieved, allowing the basic compound to be separated for further purification or characterization.

In contrast, the other options suggest alternatives that do not facilitate the specific isolation of the basic compound in the manner required. A base would not be effective in isolating the basic compound since it would not change its solubility significantly. Simply adding a solvent likely would not create the necessary phase separation to isolate the compound based on its acid-base properties. Using a general reagent on the original mixture does not specifically address the solubility differences needed for isolation. Thus, the addition of an acid to create a distinct aqueous layer containing the basic compound is the most effective