The relation between base equilibrium constant and degree of dissociation is
C x^2 = Kb
x is degree of dissociation
C x^2 = 3.3 * 10^-6
(0.17) x^2 = 3.3 * 10^-6
x = 4.24 * 10^-3
Concentration of hydroxyl ion is
[OH-] = c x = 0.17 * 4.24 * 10^-3 = 0.72 * 10^-3 M
PoH = - log [OH-] = 2.85
PH = 14 - pOH = 11.15
Hence, pH of solution is 11.15