When reacted with PABA, which bases would produce an equilibrium that favors the reactant side?

In order to determine which bases would produce an equilibrium that favors the reactant side when reacted with PABA (p-aminobenzoic acid), we need to examine the acidity and basicity of PABA and the bases.

PABA is a weak acid that can donate a proton (H+) in solution. Therefore, bases that are weaker than PABA (i.e., have a lower tendency to accept a proton) would help favor the reactant side and help maintain the acid form of PABA. Bases that are stronger than PABA (i.e., have a higher tendency to accept a proton) would favor the product side and help convert PABA into its conjugate base form.

Some examples of bases that are weaker than PABA and would favor the reactant side (acid form of PABA) in the equilibrium include:
- Sodium bicarbonate (NaHCO3)
- Sodium phosphate (Na3PO4)
- Ammonia (NH3)
- Methylamine (CH3NH2)

These bases have lower tendencies to accept a proton compared to PABA. Therefore, they would help favor the reactant side and maintain the acid form of PABA.

It is important to note that the equilibrium constant (K) of the reaction and the specific reaction conditions (such as concentration, temperature, etc.) will also influence the direction of the equilibrium. The above bases are examples, and the specific equilibrium position can vary depending on the specific conditions of the reaction.