Answer:
The concentration of H₃PO₄ will increase.
Explanation:
H₃PO₄(aq) + H₂O(l) ⇄ H₂PO₄⁻(aq) + H₃O⁺(aq)
According to Le Châtelier's Principle, when we apply a stress to a system at equilibrium, the system will respond in a way that tends to relieve the stress.
If we add more H₂PO₄⁻, the position of equilibrium will move to the left to get rid of the added H₂PO₄⁻.
The concentration of H₃PO₄ will increase.
