Your choice (4-methoxybenzoic acid) is

Let's separate 4-methoxybenzoic acid.

If you want to make only 4-methoxybenzoic acid* water soluble, which aqueous solution will you add?

dilute aqueous HCl (a strong acid)
dilute aqueous NaOH (a strong base)
saturated aqueous NaHCO3 (a weak base)

Click ADD to add the selected solution to the separatory funnel