Ammonia is a Base, use the value of its Kb to get the pOH. But first, establish a Base Dissociation Equation since it is a Weak base.
kb = ([NH4+][OH-])/[NH3]
Use the Ice Table to arrive to an equation.
1.8 x 10^-5 = x^2/ 0.01 (assuming 0.01 - x is equivalent to 0.01)
x = 4.24 x 10^-4 [OH]-
pOH = -log [OH]
pH= 14 - pOH = 10.62