EXAM PRACTICE QUESTIONS Questions 1-4 are for Test 3, Questions 5-17 are for the final. Chapter 18 1. Classify each of the following as a strong acid, strong base, weak acid, weak base, soluble salt or insoluble base in water. A) Sr(OH)2 ____________________ B) AgF ____________________ C) NaClO3 ____________________ D) Co(OH)2 ____________________ E) H2CO3 ____________________ F) HI ____________________ G) CH3NH2 ____________________ Answer: A) strong base B) soluble salt C) soluble salt D) insoluble base E) weak acid F) strong acid G) weak base 2. Calculate the Ca2+ ion concentration, the OH- ion concentration, the pOH and the pH of a 0.15 M Ca(OH)2 solution. Answer: Ca2+ = 0.15 M, OH- = 0.15 M, pOH = 0.52, pH = 13.48 3. Calculate the pH, pOH, [H+] and [OH-] of a 0.25 M HClO4 solution. Answer: [H+] = 0.25 M, [OH-] = 3.98 u 10-14 M, pOH = 13.4, pH = 0.60 4. The pH of a solution of Ba(OH)2 is 9.40. What is the molarity of this solution of base? Answer: 1.3 u 10-5 M5. Calculate the ionization constant for a weak acid, HA, that is 1.60% ionized in 0.0950 M solution. Answer: 2.43 u 10-5 M 6. The pH of a 0.10 M solution of a monoprotic acid is 2.85. What is the value of the ionization constant of the acid? Answer: 2.0 u 10-5 M 7. Calculate the value of [H3O+] in a 0.010 M HOBr solution, Ka = 2.5 u 10-9. Answer: 5.0 u 10-6 M 8. What is the percent ionization of 0.20 M HNO2? Ka = 4.5 u 10-4 Answer: 4.7% 9. The [OH-] = 1.3 u 10-6 M for a 0.025 M solution of a weak base. Calculate the value of Kb for this weak base. Answer: 6.8 u 10-11 10. The pH of a 0.12 M solution of a weak base is 10.30. What is the value of pKb for this weak base? Answer: 6.48 11. The hypothetical weak acid H2A ionizes as shown below. Calculate the [HA-] in 0.20 M H2A. H2A <=> H+ + HA- Ka1 = 1.0 u 10-7 HA- <=> H+ + A2- Ka2 = 5.0 u 10-11 Answer: 1.4 u 10-4 12. Calculate the pH of 3.2 u 10-3 M H2CO3 solution. Answer: 4.44 13. Which of the following is the strongest base? Cl- HClO2- I- NO3- __________ Answer: HClO2-14. The following salts are formed as neutralization products of acid-base reactions. Indicate whether the salts would produce acidic, basic or neutral aqueous solutions. A) NaCN _______________ B) NH4Cl _______________ C) BaBr2 _______________ D) (CH3)3NHBr _______________ E) KF _______________ Answer: A) basic B) acidic C) neutral D) acidic 15. A 0.10 M solution of which of the following salts is most basic? NaF NaNO2 NaCH3COO NaOCl NaCN __________________ Answer: NaCN 16. What is the pH of 0.35 M KOBr solution? Ka = 2.5 u 10-9 Answer: 11.07 17. Calculate the [H3O+] in 0.030 M KF. Answer: 1.5 u 10-8 M18. Calculate the pH of 0.15 M NH4NO3 solution. Answer: 5.04 19. What is the pH of 0.30 M FeCl2 solution? The hydrated ferrous ion is [Fe(OH2)6]2+. For [Fe(OH2)6]2+, Ka = 3.0 u 10-10. Answer: