Question

Calculate the pH of a 0.30 M solution of NH₄Cl. (K_b for NH₃ = 1.8 × 10^–5) 

a) 3.33 

b) 4.89 

c) 9.11 

d) 7.00 

e) 11.67 

Answer 1

The pH of a 0.30 M solution of NH₄Cl is 4.89.

Answer 2

NH4^+1 + H2O <--> H3O^+1 + NH3

Ka = [H3O+][NH4]/[NH4+]

Ka = Kw/Kb = 5.6x10^-10

Ka = 5.6x10^-10 = X^2/(0.30-X)

and solving this you will get your pH