Question

6. A0.68 M solution of a weak acid HA is 0.35 % ionized. What are the H, A, and HA concentrations at equilibrium? What is K? 7. The K, for glyoxylic acid, HC HO, is 6.6 x 104. What is the pH of a 0.45 M solution of the acid? What is the % ionization of the acid at this concentration?

Answer 1

7) C2HO3 + H Sz Hz O3 Tnifal Inital + Cx change - CX change Equillibrium C(1-x) c(-x) Equellibricom dx.cn xxxxC - Сх* Ka C1-x) = CxV ka %3D (1-x) $(1-x) Here. Here = CxY ka ka = Cx > 6-6 xi0 = ka Co.45) x 0:35 = 14.67 X10 = 0.0035 100 0-45 Ka= (0:68) (0-0035) -2 X= 3.83×10 Ka = 8.33 x 1ō6 •1. of Ionization 3.83 x10 x10o %3D = 3.83 CH+] = Cx = (0-68 x0-0035s)M [H+) = cx 2-38 x10°M = 0-45)(3-83 xiở) [A-] = = cx = 2:38 ×10°M [H+] = 0.0172M [HA] pM = - log [u+] -logho C (I-2) = 0-68 (1- 0-0035) -log (12miot) 4-logi0" [HAJ = 0.677 M 172 4-2:235 p" = =1.765