Explanation:
aam= 90%•20amu+10%•22amu/100
aam= 2020/100
aam= 20.2
I believe pH = -log[H+]
Also, 14 = pH + pOH
Therefore pH = 14 - pOH
pH = 14 - 4.01
pH = 9.99
9.99 = -log[H+]
Solve for H+