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Problem 32a
Write a chemical equation that illustrates the autoionization of water.
Problem 32b
Write the expression for the ion product constant for water, Kw.
Problem 34a
Calculate 3OH-4 for each of the following solutions, and indicate whether the solution is acidic, basic, or neutral: (a) 3H+4 = 0.0505 M
Problem 36
Deuterium oxide 1D2O, where D is deuterium, the hydrogen-2 isotope) has an ion-product constant, Kw, of 8.9 * 10-16 at 20 °C. Calculate 3D+4 and 3OD-4 for pure (neutral) D2O at this temperature.
Problem 37
By what factor does [H+] change for a pH change of (a) 2.00 units? (b) 0.50 units?
- Consider two solutions, solution A and solution B. The concentration of 3H+4 in solution A is 250 times greater than that in solution B. What is the difference in the pH values of the two solutions?
Problem 38
Problem 43b
Addition of the indicator methyl orange to an unknown solution leads to a yellow color. The addition of bromthymol blue to the same solution also leads to a yellow color. (b) What is the range (in whole numbers) of possible pH values for the solution?
Problem 44b
Addition of phenolphthalein to an unknown colorless solution does not cause a color change. The addition of bromthymol blue to the same solution leads to a yellow color. (b) Which of the following can you establish about the solution: (i) A minimum pH, (ii) A maximum pH, or (iii) A specific range of pH values?
Problem 44c
Addition of phenolphthalein to an unknown colorless solution does not cause a color change. The addition of bromthymol blue to the same solution leads to a yellow color. (c) What other indicator or indicators would you want to use to determine the pH of the solution more precisely?
- Is each of the following statements true or false? (a) All strong acids contain one or more H atoms. (b) A strong acid is a strong electrolyte. (c) A 1.0-M solution of a strong acid will have pH = 1.0.
Problem 45
- Determine whether each of the following is true or false: (a) All strong bases are salts of the hydroxide ion. (b) The addition of a strong base to water produces a solution of pH > 7.0. (c) Because Mg(OH)2 is not very soluble, it cannot be a strong base.
Problem 46
Problem 47b
Calculate the pH of each of the following strong acid solutions: (b) 1.52 g of HNO3 in 575 mL of solution
Problem 48b
Calculate the pH of each of the following strong acid solutions: (b) 0.225 g of HClO3 in 2.00 L of solution
- Calculate [OH-] and pH for (a) 1.5 × 10^-3 M Sr(OH)_2 (b) 2.250 g of LiOH in 250.0 mL of solution (c) 1.00 mL of 0.175 M NaOH diluted to 2.00 L (d) a solution formed by adding 5.00 mL of 0.105 M KOH to 15.0 mL of 9.5 × 10^-2 M Ca(OH)_2.
Problem 49
Problem 50c
Calculate [OH-] and pH for each of the following strong base solutions: (c) 10.0 mL of 0.0105 M Ca(OH)2 diluted to 500.0 mL
Problem 52
Calculate the concentration of an aqueous solution of Ca1OH22 that has a pH of 10.05.
- Write the chemical equation and the Ka expression for the ionization of each of the following acids in aqueous solution. First, show the reaction with H+(aq) as a product and then with the hydronium ion: (a) HBrO2 (b) C2H5COOH.
Problem 53
Problem 54
Write the chemical equation and the Ka expression for the acid dissociation of each of the following acids in aqueous solution. First show the reaction with H+(a)q as a product and then with the hydronium ion: (a) C6H5COOH (b) HCO3-
- Lactic acid CH3CH(OH)COOH has one acidic hydrogen. A 0.10 M solution of lactic acid has a pH of 2.44. Calculate Ka.
Problem 55
Problem 57
A 0.100 M solution of chloroacetic acid 1ClCH2COOH2 is 11.0% ionized. Using this information, calculate 3ClCH2COO-4, 3H+4, 3ClCH2COOH4, and Ka for chloroacetic acid.
- A particular sample of vinegar has a pH of 2.90. If acetic acid is the only acid that vinegar contains (Ka = 1.8 * 10^-5), calculate the concentration of acetic acid in the vinegar.
Problem 59
Problem 60
If a solution of HF 1Ka = 6.8 * 10-42 has a pH of 3.65, calculate the concentration of hydrofluoric acid.
- The acid-dissociation constant for benzoic acid C6H5COOH is 6.3 * 10^-5. Calculate the equilibrium concentrations of H3O+, C6H5COO-, and C6H5COOH in the solution if the initial concentration of C6H5COOH is 0.050 M.
Problem 61
Problem 62
The acid-dissociation constant for chlorous acid 1HClO22 is 1.1 * 10-2. Calculate the concentrations of H3O+, ClO2-, and HClO2 at equilibrium if the initial concentration of HClO2 is 0.0125 M.
Problem 63a,b
Calculate the pH of each of the following solutions (Ka and Kb values are given in Appendix D): (a) 0.095 M propionic acid (C2H5COOH) (b) 0.100 M hydrogen chromate ion (HCrO4-)
- Saccharin, a sugar substitute, is a weak acid with pKa = 2.32 at 25 °C. It ionizes in aqueous solution as follows: HNC7H4SO31(aq) ⇌ H+(aq) + NC7H4SO3-(aq). What is the pH of a 0.10 M solution of this substance?
Problem 65
- The active ingredient in aspirin is acetylsalicylic acid 1HC9H7O42, a monoprotic acid with Ka = 3.3 * 10^-4 at 25 °C. What is the pH of a solution obtained by dissolving two extra-strength aspirin tablets, each containing 500 mg of acetylsalicylic acid, in 250 mL of water?
Problem 66
- Calculate the percent ionization of hydrazoic acid (HN3) in solutions of each of the following concentrations (Ka is given in Appendix D): (a) 0.400 M, (b) 0.100 M, (c) 0.0400 M.
Problem 67
Problem 68
Calculate the percent ionization of propionic acid (C2H5COOH) in solutions of each of the following concentrations (Ka is given in Appendix D): (a) 0.250 M (b) 0.0800 M (c) 0.0200 M
Problem 69
Citric acid, which is present in citrus fruits, is a triprotic acid (Table 16.3). (a) Calculate the pH of a 0.040 M solution of citric acid. (b) Did you have to make any approximations or assumptions in completing your calculations? (c) Is the concentration of citrate ion 1C6H5O7 3-2 equal to, less than, or greater than the H+ ion concentration?