2. Calculate Ka for NH4+ ion using Kb for NH3 (1.8 x 10-5). Compare this value with the one calculated from your measured pH value (higher, lower, or the same).

Answer 1

Recall that KaKb = Kw = 1x10^-14

Ka = 1x10^-14 / Kb

Ka = 1x10^-14 / 1.8x10^-5

Ka = 5.56x10^-10

Now you'll have to compare this to your calculated value.