So Kb is the constant for the rxn
B- + H2O <-> BH + OH-
With B- being your base, the hypochlorite anion, dissociated from the Na. The ice table you used is great! You found x! But look at the the x corresponds to - OH-. So taking -log(x) like you did led you to find -log(OH-). So you found pOH. So take 14-pOH to find your pH!