Ch.16 - Aqueous Equilibria: Acids & Bases
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- Calculate the pH and the concentrations of all species present (H2C8H4O4, HC8H4O4-, C8H4O4 2-, H3O+, and OH-) in a 0.0250 M solution of phthalic acid, H2C8H4O4, with pKa1 = 2.89 and pKa2 = 5.512.
Problem 111
- Write a balanced net ionic equation and the corresponding equilibrium equation for the reaction of the following weak bases with water. (c) Cyanide ion, CN
Problem 112
- Which of the following compounds are more soluble in acidic solution than in pure water? Write a balanced net ionic equation for each dissolution reaction. (a) AgBr
Problem 113
- Strychnine 1C21H22N2O22, a deadly poison used for killing rodents, is a weak base having Kb = 1.8 * 10-6. Calculate the pH of a saturated solution of strychnine (16 mg/100 mL).
Problem 114
- Oxycodone 1C18H21NO42, a narcotic analgesic, is a weak base with pKb = 5.47. Calculate the pH and the concentrations of all species present (C18H21NO4, HC18H21NO4 + , H3O+ , and OH-) in a 0.002 50 M oxycodone solution.
Problem 118
- Morpholine C4H9NO is a weak organic base with pKb = 5.68. Calculate the pH and the concentrations of all species present (C4H9NO, HC4H9NO+, and OH-) in a 0.0100 M morpholine solution.
Problem 119
- Using values of Kb in Appendix C, calculate values of Ka for each of the following ions. (a) Propylammonium ion, C3H7NH3+
Problem 120
- Using values of Ka in Appendix C, calculate values of Kb for each of the following ions. (a) Fluoride ion, F-
Problem 121
- Nicotine 1C10H14N22 can accept two protons because it has two basic N atoms 1Kb1 = 1.0 * 10-6; Kb2 = 1.3 * 10-112. Calculate the values of Ka for the conjugate acids C10H14N2H+ and C10H14N2H22 + .
Problem 122
- Sodium benzoate (C6H5CO2Na) is used as a food preservative. Calculate the pH and the concentrations of all species present (Na+, C6H5COO-, C6H5COOH, H3O+, and OH-) in 0.050 M sodium benzoate; Ka for benzoic acid (C6H5COOH) is 6.5 * 10^-5.
Problem 123
- Write a balanced net ionic equation for the principal reaction in solutions of each of the following salts. In each case, identify the Brønsted–Lowry acids and bases and the conjugate acid–base pairs. (a) Na2CO3
Problem 125
- Classify each of the following ions according to whether they react with water to give a neutral, acidic, or basic solution. (a) F-
Problem 126
- Classify each of the following salt solutions as neutral, acidic, or basic. See Appendix C for values of equilibrium constants. (a) Fe1NO323
Problem 127
- Calculate the concentrations of all species present and the pH in 0.10 M solutions of the following substances. See Appendix C for values of equilibrium constants. (b) Sodium acetate, Na1CH3CO22
Problem 128
- Calculate the pH and the percent dissociation of the hydrated cation in 0.020 M solutions of the following substances. See Appendix C for values of equilibrium constants. (a) Fe1NO322
Problem 129
- Calculate Ka for the cation and Kb for the anion in an aqueous NH4CN solution. Is the solution acidic, basic, or neutral?
Problem 130
- Classify each of the following salt solutions as acidic, basic, or neutral: (a) KBr (b) NaNO2 (c) NH4Br (d) ZnCl2 (e) NH4F
Problem 131
- The hydrated cation M1H2O26 3 + has Ka = 10-4, and the acid HA has Ka = 10-5. Identify the principal reaction in an aqueous solution of each of the following salts, and classify each solution as acidic, basic, or neutral. (a) NaA
Problem 132
- Classify each of the following salt solutions as neutral, acidic, or basic. See Appendix C for values of equilibrium constants. (a) NH4F (b) (NH4)2SO3
Problem 133
- Calculate the pH and the percent dissociation of the hydrated cation in the following solutions. See Appendix C for the value of the equilibrium constant. (a) 0.010 M Cr1NO323
Problem 135
- Baking powder contains baking soda, NaHCO3, and an acidic substance such as sodium alum, NaAl(SO4)2 ~ 12 H2O. These components react in an aqueous medium to produce CO2 gas, which “raises” the dough. Write a balanced net ionic equation for the reaction.
Problem 136
- Arrange the following substances in order of increasing H3O+ concentration for a 0.10 M solution of each. (a) Zn(NO3)2 (b) Na2O (c) NaOCl (d) NaClO4 (e) HClO4
Problem 137
- For each of the Lewis acid–base reactions in Problem 16.139, draw electron-dot structures for the reactants and products, and use the curved arrow notation to represent the donation of a lone pair of electrons from the Lewis base to the Lewis acid.
Problem 141
- Classify each of the following as a Lewis acid or a Lewis base. (e) OH-
Problem 142
- Which would you expect to be the stronger Lewis acid in each of the following pairs? Explain. (a) BF3 or BH3
Problem 143
- When NO2 is bubbled into water, it is completely converted to HNO3 and HNO2: 2 NO21g2 + H2O1l2S HNO31aq2 + HNO21aq2 Calculate the pH and the concentrations of all species present (H3O+ , OH-, HNO2, NO2 -, and NO3 -) in a solution prepared by dissolving 0.0500 mol of NO2 in 1.00 L of water. Ka for HNO2 is 4.5 * 10-4.
Problem 147
- Acid and base behavior can be observed in solvents other than water. One commonly used solvent is dimethyl sulfoxide (DMSO), which can be treated as a monoprotic acid 'HSol.' Just as water can behave either as an acid or a base, so HSol can behave either as a Brønsted–Lowry acid or base. (b) The weak acid HCN has an acid dissociation constant Ka = 1.3 * 10-13 in the solvent HSol. If 0.010 mol of NaCN is dissolved in 1.00 L of HSol, what is the equilibrium concentration of H2Sol + ?
Problem 151
- In the case of very weak acids, 3H3O+ 4 from the dissociation of water is significant compared with 3H3O+ 4 from the dissociation of the weak acid. The sugar substitute saccharin 1C7H5NO3S2, for example, is a very weak acid having Ka = 2.1 * 10-12 and a solubility in water of 348 mg/100 mL. Calculate 3H3O+ 4 in a saturated solution of saccharin. (Hint: Equilibrium equations for the dissociation of saccharin and water must be solved simultaneously.)
Problem 153
- In aqueous solution, sodium acetate behaves as a strong electrolyte, yielding Na+ cations and CH3CO2 - anions. A particular solution of sodium acetate has a pH of 9.07 and a density of 1.0085 g/mL. What is the molality of this solution, and what is its freezing point?
Problem 154
Problem 155a
During a certain time period, 4.0 million tons of SO2 were released into the atmosphere and subsequently oxidized to SO3. As explained in the Inquiry, the acid rain produced when the SO3 dissolves in water can damage marble statues: CaCO3(s) + H2SO4(aq) → CaSO4(aq) + CO2(g) + H2O(l) (a) How many 500 pound marble statues could be damaged by the acid rain? (Assume that the statues are pure CaCO3 and that a statue is damaged when 3.0% of its mass is dissolved.)