Acid-Base Equilibria Questions PDF

1. What is the Brønsted-Lowry de nition of an acid? * A) A proton acceptor. * B) A proton donor. * C) An electron pair acceptor. * D) An electron pair donor. 2. What is the Brønsted-Lowry de nition of a base? * A) A proton acceptor. * B) A proton donor. * C) An electron pair acceptor. * D) An elect...

1. What is the Brønsted-Lowry de nition of an acid? * A) A proton acceptor. * B) A proton donor. * C) An electron pair acceptor. * D) An electron pair donor. 2. What is the Brønsted-Lowry de nition of a base? * A) A proton acceptor. * B) A proton donor. * C) An electron pair acceptor. * D) An electron pair donor. 3. What is a conjugate acid-base pair? * A) Two acids that differ by a proton. * B) Two bases that differ by a proton. * C) A base and an acid that differ by a proton. * D) Any acid and any base. 4. What is the formula for calculating pH? * A) pH = log10[H+] * B) pH = -log10[H+] * C) pH = 10-[H+] * D) pH = [H+] 5. What is the pH of a solution with [H+] = 1 x 10-5 mol dm-3? * A) 1 * B) 5 * C) 9 * D) 14 6. What is the [H+] of a solution with a pH of 3? * A) 1.0 x10-11 moldm-3 * B) 3 moldm-3 * C) 1.0 x103 moldm-3 * D) 1.0 x10-3 moldm-3 7. What is a strong acid? * A) An acid that is concentrated. * B) An acid that fully dissociates in aqueous solution. * C) An acid that partially dissociates in aqueous solution. fi fi * D) An acid that does not dissociate in aqueous solution. 8. What is the pH of a 0.1 mol dm-3 solution of HCl (a strong acid)? * A) 0.1 * B) 1 * C) 2 * D) 13 9. What is the ionic product of water, Kw? * A) Kw = [H+][OH-] * B) Kw = [H+] / [OH-] * C) Kw = [H2O] * D) Kw = [H+]2[O2] 10. What is the value of Kw at 298 K? * A) 1 x 10-7 mol2 dm-6 * B) 1 x 10-14 mol2 dm-6 * C) 1 x 107 mol2 dm-6 * D) 1 x 1014 mol2 dm-6 11. What is the pH of pure water at 298K? * A) 1 * B) 6 * C) 7 * D) 14 12. What is a weak acid? * A) An acid that is not very concentrated. * B) An acid that fully dissociates in aqueous solution. * C) An acid that partially dissociates in aqueous solution. * D) An acid that reacts slowly. 13. What is the expression for the acid dissociation constant, Ka, for a weak acid, HA? * A) Ka = ([H+][A-]) / [HA] * B) Ka = [HA] / ([H+][A-]) * C) Ka = [H+][HA] / [A-] * D) Ka = [A-] / [H+][HA] 14. What does a large value of Ka indicate for a weak acid? * A) a stronger acid * B) A weaker acid * C) high pH * D) Low pH 15. What is the relationship between Ka and pKa? * A) pKa = log10[Ka] * B) pKa = -log10 Ka * C) pKa = 10^Ka * D) pKa = 1/Ka 16. Ethanoic acid is a weak acid with a Ka of 1.74 x 10-5 mol dm-3. What is the pH of a 0.1 mol dm-3 solution of ethanoic acid? (Assume [HA]eqm ≈ [HA]initial) * A) 1.0 * B) 2.9 * C) 5.7 * D) 8.2 17. What is the pH of a 0.2 mol dm-3 solution of NaOH (a strong base)? * A) 0.7 * B) 1.7 * C) 12.3 * D) 13.3 18. What is a buffer solution? * A) A solution with a pH of 7. * B) A solution that resists changes in pH when small amounts of acid or base are added. * C) A solution that changes color with pH. * D) A solution of a strong acid and a strong base. 19. What are the two components of a buffer solution? * A) A strong acid and its conjugate base. * B) A strong base and its conjugate acid. * C) A weak acid and its conjugate base or a weak base and its conjugate acid. * D) A strong acid and a strong base. 20. How does a buffer solution work? * A) By neutralizing any added acid or base. * B) By shifting the equilibrium to counteract the addition of acid or base. * C) By providing a large reservoir of H+ and OH- ions. * D) Both A and B 21. Which of the following combinations would make a good buffer solution? * A) HCl and NaCl * B) NaOH and NaCl * C) CH3COOH and CH3COONa * D) H2SO4 and Na2SO4 22. What is the Henderson-Hasselbalch equation? * A) pH = pKa + log10([acid]/[conjugate base]) * B) pH = pKa + log10([conjugate base]/[acid]) * C) pH = pKa - log10([acid]/[conjugate base]) * D) pH = pKa - log10([conjugate base]/[acid]) 23. A buffer solution contains 0.1 mol dm-3 ethanoic acid and 0.2 mol dm-3 sodium ethanoate. The pKa of ethanoic acid is 4.76. What is the pH of the buffer? * A) 4.46 * B) 4.76 * C) 5.06 * D) 9.24 24. What happens to the pH of an acidic buffer solution when a small amount of strong acid is added? * A) It increases signi cantly. * B) It decreases signi cantly. * C) It stays approximately the same. * D) It becomes neutral. 25. On a pH titration curve for a strong acid and a strong base, what is the pH at the equivalence point? * A) 3 * B) 7 * C) 11 * D) Depends on the acid and base fi fi 26. On a pH titration curve for a weak acid and a strong base, what is the pH at the equivalence point? * A) Less than 7 * B) Equal to 7 * C) Greater than 7 * D) Depends on the acid and base 27. How would the end-point of a titration of a strong acid and a weak base compare to a strong acid strong base titration? * A) less than pH 7 * B) Equal to 7 * C) Greater than pH 7 * D) It would be the same 28. What is an appropriate indicator for a titration between a strong acid and a strong base? * A) Methyl orange (pH range 3.1-4.4) * B) Phenolphthalein (pH range 8.3-10.0) * C) Either methyl orange or phenolphthalein * D) Neither methyl orange nor phenolphthalein 29. Why is an indicator suitable for a titration? * A) It changes color rapidly over a small pH range. * B) It changes color slowly over a wide pH range. * C) It is a buffer solution. * D) It reacts with the acid or base. 30. At the half-equivalence point in a weak acid-strong base titration, what is the relationship between pH and pKa? *A) pH >> pKa * B) pH = pKa * C) pH