21. The K, value for an acid is 1.0 x 10-7. What is the Ks value for its conjugate base? a) 1.0 x 10-2 b) 1.0 x 10 c) 1.0 x 10-10 d) 1.0 x 10-12 22. Which one of the following species can act both as a Bronsted-Lowry acid and base in aqueous solutions? a) CH,COOH b) NO, c) H2PO. d) : 23. A student carried out a titration and obtained the curve below. The experimental setup could have had: 14 12 10 8 6 4 2 0 0 10 30 40 20 V(mL) 50 a) Sodium hydroxide in the burette and hydrochloric acid in the receiving flask b) Aqueous ammonia in the burette and hydrobromic acid in the receiving flask c) Hydrofluoric acid in the burette and potassium hydroxide in the receiving flask d) Nitric acid in the burette and aqueous ammonia in the receiving flask 25. Which is the strongest reducing agent according to the spontaneous reactions below? 2Cris) + 3Feaa) 2Craq) + 3Few Felu + Pb2aal Fe?aa) + Pbis) a) Cro b) Cri) c) Pb d) Pb