Question

When a 17.5 mL sample of a 0.433 M aqueous acetic acid solution is titrated with a 0.462 M aqueous barium hydroxide solution, what is the pH after 12.3 mL of barium hydroxide have been added? pH = Submit Answer Retry Entire Group 9 more group attempts remaining

Answer 1

17.5 mLx 0.433 M a) Concentration of CH COOH, CH,COOH) = : = 0.254 M (17.5+12.3) mL 2.3 mL x 0.462M Concentration of OHⓇ added= Ba = 0.381 M (17.5+12.3) mL) ICE table: CH,COOH + OH - CH,000- + H,0 I(M): 0.254 0.381 C(M): -0.254 -0.254 +0.254 E(M): 0 0.127 0.254 According to the equilibrium table, [OH-] = (x) M = 0.127 M 1.0x10-14 According to ionic product of water, Hz 10.127 = 7.87x10-14 M pH = -log[H3O+]=-log(7.87x10-24) = 13.10 - - - - - - - - - - - - - - - - - - - - - - - 36.7 mLx 0.371 M b) Concentration of CH,COOH, (CHCOOH) = 3 = 0.286 M (36.7 +10.9) mL at] 10.9 mL x 0.377 M Concentration of OH added = [NaOH]=> -= 0.0863 M (36.7+10.9) mL ICE table: CH,COOH + OH- -→ CH,COO- + H2O I(M): 0.286 0.0863 C(M): -0.0863 -0.0863 +0.0863 E(M): 0.1997 0 0.0863 PK, of CH,COOH = -log K, = -log(1.8x10-) = 4.74 According to Henderson equation, [CH,000] pH = pK+10g CH-COOH) = 4.74+108 0.1997 0.0863 = 4.38