17. Acid and Base Equilibrium

Multiple Choice

An unknown weak base has an initial concentration of 0.750 M with a pH of 8.03. Calculate its equilibrium base constant.

120

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Solve an equilibrium problem (using an ICE table) to calculate the pH of each solution. b. a solution that is 0.16 M in NH3 and 0.22 M in NH4Cl

805

Solve an equilibrium problem (using an ICE table) to calculate the pH of each solution. b. 0.15 M NaF

395

Determine the pH of each of the following solutions (Ka and Kb values are given in Appendix D): (c) 0.165 M hydroxylamine.

985

Calculate the pH of 100.0 mL of 0.30 M NH3 before and after the addition of 4.0 g of NH4NO3, and account for the change. Assume that the volume remains constant.

488

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.

354

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?

1964

Using data from Appendix D, calculate 3OH-4 and pH for each of the following solutions: (b) 0.035 M Na2S

505

Determine the [OH-], pH, and pOH of a 0.15 M ammonia solution.

1435

Caffeine (C8H10N4O2) is a weak base with a pKb of 10.4. Calculate the pH of a solution containing a caffeine concentration of 455 mg>L.

2962

Amphetamine (C9H13N) is a weak base with a pKb of 4.2. Calculate the pH of a solution containing an amphetamine concentration of 225 mg>L.

2197

Morphine is a weak base. A 0.150 M solution of morphine has a pH of 10.7. What is Kb for morphine?

3008

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Determine the [OH-] and pH of a solution that is 0.140 M in F-.

1513

Calculate the concentration of all species in a 0.15 M KF solution.

1547

Calculate the concentration of all species in a 0.225 M C6H5NH3Cl solution.

1475

Butyric acid is responsible for the foul smell of rancid butter. The pKa of butyric acid is 4.84. (c) Calculate the pH of a 0.050 M solution of sodium butyrate.

939

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).

440

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.

611

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Lactic acid is a weak acid found in milk. Its calcium salt is a source of calcium for growing animals. A saturated solution of this salt, which we can represent as Ca(Lact)2, has a [Ca2 + ] = 0.26 M and a pH = 8.78. Assuming the salt is completely dissociated, calculate the Ka of lactic acid.

2556

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 + ?

783

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?

1237

What is the pH of a 0.320 M solution of Ca(NO₂)₂ (ka of HNO₂ is 4.5 × 10^-4)?

What is the pH of a 0.750 M solution of NaCN (K_a of HCN is 4.9 × 10^-10)?

How can the pH of a solution be calculated if the pOH is known?

The K_b of methylamine is 4.4 x 10^–4. What is the approximate [OH^–] of a 1 M solution of methylamine?

calculate the pH of a 0.10 M solution of hydrazine, N₂H₄ . K_b for hydrazine is 1.3×10⁻⁶ .

What is the [OH⁻] of a 1.40 m solution of pyridine (C₅H₅N, K_b = 1.70 × 10⁻⁹)?

What is the [OH^-] of a 1.40 M solution of pyridine (C₅H₅N, K_b = 1.70 × 10^-9)?

What is the pH of a solution with a hydroxyl ion (OH^-) concentration of 10^-10 M?

The pOH of a solution is 10.75. What is the concentration of OH^– ions in the solution?

Determine the pH of a 0.227 M C₅H₅N solution at 25 °C. The K_b of C₅H₅N is 1.7 x 10^-9.

The pH of 2.65 m CH₃NH_2(aq) is 12.54. determine the value of K_b for methylamine.

491

An unknown weak base with a concentration of 0.170 M has a ph of 9.42. What is the K_b of this base?

What is the pH of a 0.300 M solution of aniline (C₆H₅NH₂, K_b = 4.3 × 10⁻¹⁰)?

What is the pH of a 0.300 m solution of aniline (C₆H₅NH₂, K_b = 4.3 × 10⁻¹⁰)?

What is the pH of a 0.420 M solution of C₅H₅NHBr (K_b of C₅H₅NH is 1.7 × 10^-9)?

Morphine is a weak base. a 0.150 m solution of morphine has a pH of 10.5. What is the K_b for morphine?

The pH of 2.65 M CH₃NH₂(aq) is 12.54. Determine the value of K_b for methylamine.

Determine the pH of a 0.227 M C₅H₅N solution at 25°C. The K_b of C₅H₅N is 1.7 x 10^-9.