acid base equilibrium

Calculate the pH for each of the following cases in the titration of 50.0 mL of 0.200 M HClO(aq) with 0.200 M KOH(aq). The ionization constant for HClO is 4.0*10^-8

(a) before addition of any KOH (b) after addition of 25.0 mL of KOH (c) after addition of 40.0 mL of KOH (d) after addition of 50.0 mL of KOH (e) after addition of 60.0 mL of KOH

I have two questions: The first is why do I have to set up a rice table for the first question? Can't I simply plug in the answers into pKa=-log(Ka)?

Second one: How do I solve it using the henderson hasslebach equation? do I find the concentration of The initial KOH and then solve? I keep getting wrong answers...