Question

2. (a) Use the letters A and B to identify the acid (A) and base (B) on the left side of the equilibrium arrow and on the right side of the equilibrium arrow. HPO4 + H3O⇆H2PO4 + H2O (b) If you added more H2PO to this reaction system, would the concentration of HPO increase or decrease? Explain. (c) If you added more HPO4 to this reaction system, would the pH increase or decrease?

Answer 1

In a chemical equilibrium, HPO4 is the base and H3O is the acid initially. Adding more H2PO based on the assumption that it is a typo and was meant to indicate H2PO4, should decrease HPO4 concentration, and hence pH should decrease too.

Step-by-step explanation:

In the given equilibrium reaction, HPO4 can be labeled as Base (B) as it accepts a proton from H3O (which will be the Acid (A)) to form H2PO4. The reverse reaction sees H2PO4 (now the base) donate a proton to H2O (now the acid) to reform HPO4 and H3O.

Adding more H2PO should decrease the concentration of HPO4 according to Le Chatelier's principle since the system would shift towards the right to minimize the change. However, the typo in the question (should be H2PO4) makes this part of the question unclear.

Adding more HPO4 will cause the reaction to shift toward the right to react with the increased HPO4, thus increasing the concentration of H3O and ultimately, due to H3O being directly proportional to pH, the pH should decrease.

Learn more about Acid-Base Equilibrium