13) Which one of the following is the weakest acid? A) HF (K-68x10-4) Acetic acid (Ka-1.8 x 10-5) NO (K-4510-4) D) HCIO (K-3.0 x 10-8) CN (K-49x10-10) 14) HZ is a weak acid. An aqueous solution of HZ is prepared by dissolving 0.020 mol of HZ in sufficient water to yield 1.00 L of solution. The pH of the solution was 4.93 at 25C. The Ka of HZ. is. 5.9 x 10-9 B) 1.4 x 10-10 (12-10-5 D) 2.8 10-12 E) 9.910-2 15) The K, of hypochlorous acid (HCIO) is 3.0 x 10-8 at 25C. What is the % ionization of hypochlorous acid in a 0.015-M aqueous solution of HCIO at 25C? A) 1.4 x 10-3 B) 14 2.1 x 10-5 D) 4.5 x 10-8 E) 0.14 16) The pH of a 0.55-M aqueous solution of hypobromous acid, HBrO, at 25C is 4.48. What is the value of Ka for HBrO? A) 3.3 x 10-5 E) 3.0 104 B) 2.0 x 10-9 C) 6.0 x 10-5 D) 1.1 x 10-9 17) The Ka of hypochlorous acid (HCIO) is 3.0 x 10-8. What is the pH at 25C of an aqueous solution that is 0.020 M in HCIO? A) +2.45 C) -9.22 D) +9.22 E) +4.61 18) The acid-dissociation constants of phosphoric acid (H3PO4) are Kal -7.5 x 10-3, Ka2-6.2 x 10-8, and Ka3-4.2 x 10-13 at 25C. What is the pH of a 2.5-M aqueous solution of phosphoric acid? A) 0.13 B) 1.8 C) 2.5 D) 0.40 B)-2.45 19) B is a weak base. Which equilibrium corresponds to the equilibrium constant Ka for HB*? A) HB+ (aq) + H3O+ (aq) B) B (aq) + HO(1) C) HB+ (aq) + OH- (aq) D) B (aq) + H3O+ (aq) E) HB+ (aq) + H0 (1) 21) Ammonia is a A) weak base HB2+ (aq) + H0 (1) HB+ (aq) + OH- (aq) B (aq) + HO (1) HB+ (aq) + H0 (1) B (aq) H3O+ (aq) + 20) The acid-dissociation constant for chlorous acid, HCIO2, at 25C is 1.0 x 10-2, Calculate the concentration of H+ if the initial concentration of acid is 0.100 M... A) 1.0 x 10-3 B) 1.0 x 10-2 E) 3.2 x 10-2 C) 2.7 x 10-2 D) 3.7 x 10-2 B) strong acid C) salt D) strong base 22) The pH of a 0.10-M solution of a weak base is 9.82. What is the Ky, for this base? B) 2.0 x 10-5 A) 4.3 x 10-8 C) 6.6 x 10-4 D) 2.1 x 10-4 2 E) 0.87 E) weak acid E) 8.8 x 10-8