hitunglah pH larutan amonium karbonat 0,1 molar jika Ka asam karbonat = 10-4 dan Kb amonium hidroksida 10-6

Ph ( NH4 )2CO3 0.1 M = ???
Kb H2CO3 = 10^-4
Kb NH4OH = 10^-6

Ka > Kb maka Ph < 7

Ph total = 1/2 ( 14 + PhKa-PhKb)
= 1/2 ( 14 + (-log 10^-4) - (-log^-6)
= 1/2 ( 14 + 4 - 6)
= 1/2 ( 18-6)
= 1/2.12
= 6 ( lihat di internet rumusnya)