Respuesta :

 Best Answer:  (a) 
8.9 x 10^-7 = x^2 / 0.15-x 
x = [OH-] = 0.00037 M 
pOH = 3.4 
pH = 14 - 3.4 = 10.6 

(b) 
Ka = Kw/Kb = 5.6 x 10^-10 = x^2 / 0.20-x 
x = [H+] = 0.000011 M 
pH = 5.0