A solution is initially 0.050M in acetate, CH3COO- (Kb = 5.6 x 10^-10). 10.0mL of 0.10 M HCl is added to 50.0mL of the acetate solution. The Ka for the conjugate weak acid of CH3CHOO- is 1.8 x 10^-5. Calculate the pH for this solution at equilibrium.