Back
Problem 70c
Write the chemical equation and the Kb expression for the reaction of each of the following bases with water: (c) benzoate ion, C6H5CO2-
- Calculate the molar concentration of OH- in a 0.075 M solution of ethylamine (C2H5NH2); Kb = 6.4 * 10^-4. Calculate the pH of this solution.
Problem 71
- Calculate the molar concentration of OH- in a 0.724 M solution of hypobromite ion BrO-; Kb = 4.0 * 10^-6. What is the pH of this solution?
Problem 72
Problem 73a
Ephedrine, a central nervous system stimulant, is used in nasal sprays as a decongestant. This compound is a weak organic base: C10H15ON1aq2 + H2O1l2 Δ C10H15ONH+1aq2 + OH-1aq2 A 0.035 M solution of ephedrine has a pH of 11.33. (a) What are the equilibrium concentrations of C10H15ON, C10H15ONH+, and OH-?
Problem 73b
Ephedrine, a central nervous system stimulant, is used in nasal sprays as a decongestant. This compound is a weak organic base: C10H15ON1aq2 + H2O1l2 Δ C10H15ONH+1aq2 + OH-1aq2 A 0.035 M solution of ephedrine has a pH of 11.33. (b) Calculate Kb for ephedrine.
Problem 74
Codeine 1C18H21NO32 is a weak organic base. A 5.0 * 10-3M solution of codeine has a pH of 9.95. Calculate the value of Kb for this substance. What is the pKb for this base?
- Phenol, C6H5OH, has a Ka of 1.3 * 10^-10. (c) Is phenol a stronger or weaker acid than water?
Problem 75
Problem 76
Use the acid-dissociation constants in Table 16.3 to arrange these oxyanions from strongest base to weakest: SO42-, CO32-, SO32-, and PO43-.
Problem 77a
Given that Ka for acetic acid is 1.8 * 10-5 and that for hypochlorous acid is 3.0 * 10-8, which is the stronger acid?
Problem 77b
Which is the stronger base, the acetate ion or the hypochlorite ion?
Problem 77c
Calculate Kb values for CH3COO- and ClO-.
Problem 78a
Given that Kb for ammonia is 1.8 × 10-5 and that for hydroxylamine is 1.1 × 10-8, which is the stronger base?
Problem 78b
Which is the stronger acid, the ammonium ion or the hydroxylammonium ion?
- Using data from Appendix D, calculate [OH-] and pH for each of the following solutions: (a) 0.10 M NaBrO (b) 0.080 M NaHS (c) a mixture that is 0.10 M in NaNO2 and 0.20 M in Ca(NO3)2.
Problem 79
Problem 80b
Using data from Appendix D, calculate 3OH-4 and pH for each of the following solutions: (b) 0.035 M Na2S
- A solution of sodium acetate (NaCH3COO) has a pH of 9.70. What is the molarity of the solution?
Problem 81
Problem 82a
Pyridinium bromide 1C5H5NHBr2 is a strong electrolyte that dissociates completely into C5H5NH+ and Br-. An aqueous solution of pyridinium bromide has a pH of 2.95. (a) Write out the reaction that leads to this acidic pH.
Problem 82b
Pyridinium bromide 1C5H5NHBr2 is a strong electrolyte that dissociates completely into C5H5NH+ and Br-. An aqueous solution of pyridinium bromide has a pH of 2.95. (b) Using Appendix D, calculate the Ka for pyridinium bromide.
Problem 82c
Pyridinium bromide 1C5H5NHBr2 is a strong electrolyte that dissociates completely into C5H5NH+ and Br-. An aqueous solution of pyridinium bromide has a pH of 2.95. (c) A solution of pyridinium bromide has a pH of 2.95. What is the concentration of the pyridinium cation at equilibrium, in units of molarity?
- Predict whether aqueous solutions of the following compounds are acidic, basic, or neutral: (a) NH4Br (b) FeCl3 (c) KClO4 (d) NaHC2O4.
Problem 83
Problem 83c
Predict whether aqueous solutions of the following compounds are acidic, basic, or neutral: (c) Na2CO3
Problem 84a
Predict whether aqueous solutions of the following substances are acidic, basic, or neutral: (a) AlCl3
Problem 84b
Predict whether aqueous solutions of the following substances are acidic, basic, or neutral: (b) NaBr
Problem 84c
Predict whether aqueous solutions of the following substances are acidic, basic, or neutral: (c) NaClO
Problem 84d
Predict whether aqueous solutions of the following substances are acidic, basic, or neutral: (d) 3CH3NH34NO3
Problem 84e
Predict whether aqueous solutions of the following substances are acidic, basic, or neutral: (e) Na2SO3.
Problem 85
An unknown salt is either NaF, NaCl, or NaOCl. When 0.050 mol of the salt is dissolved in water to form 0.500 L of solution, the pH of the solution is 8.08. What is the identity of the salt?
Problem 86
An unknown salt is either KBr, NH4Cl, KCN, or K2CO3. If a 0.100 M solution of the salt is neutral, what is the identity of the salt?
- Predict the stronger acid in each pair: (a) HNO3 or HNO2 (b) H2SO4 or H2SeO4 (c) CH3COOH or CCl3COOH.
Problem 87
- Predict the stronger acid in each pair: (b) H3PO4 or H3AsO4 (d) H2C2O4 or HC2O4⁻
Problem 88