5. Find the pH of a 0.65 M solution of propionic acid. What is the fraction ionized at equilibrium? 6. What is the conjugate base of NH4+? 7. What is the conjugate base of hydrazoic acid? For any general weak acid, HA, HA(aq) + H2O(l) H3O+(aq)+ A-(aq) and Ka = a) What is the conjugate base of HA? C) Write the equilibrium expression for this reaction. Is this the same as the Ka expression? What is different? D) Ka values are ionization constants for weak acids in water.