Question

A buffer solution is prepared in which the concentration of NH₃ is 0.30M and the concentration of NH₄⁺ is 0.20M. If the equilibrium constant, K_b for NH₃ equals 1.8 x 10^-5, what is the pH of the solution?

(a) 8.73
(b) 9.08
(c) 9.43
(d) 11.72

Answer 1

Correct option is (c) 9.43

= 4.74 – 0.176 = 4.56

pH = 14 – pOH = 14 – 4.56 = 9.44