Chapter 3.4, Problem 3.10.1PE

For the generic equilibrium $HA\left(aq\right)\rightleftharpoons H^{+}\left(aq\right)+A^{-}\left(aq\right)$ , which of these statements is true?

1. The equilibrium constant for this reaction changes as the pH changes.
2. If you add the soluble salt KA to a solution of HA that is at equilibrium, the concentration of HA would decrease.
3. If you add the soluble salt KA to a solution of HA that is at equilibrium, the concentration of A - would decrease.
4. If you add the soluble salt KA to a solution of HA that is at equilibrium, the pH would increase.