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- Which of the following salts will be substantially more soluble in acidic solution than in pure water: (a) ZnCO3, (b) ZnS, (c) BiI3, (d) AgCN, (e) Ba3(PO4)2?
Problem 63
Problem 64
For each of the following slightly soluble salts, write the net ionic equation, if any, for reaction with a strong acid: (a) MnS (b) PbF2 (c) AuCl3 (e) CuBr (d) Hg2C2O4.
Problem 65
From the value of Kf listed in Table 17.1, calculate the concentration of Ni2 +1aq2 and Ni1NH326 2+ that are present at equilibrium after dissolving 1.25 g NiCl2 in 100.0 mL of 0.20 M NH31aq2.
- From the value of Kf listed in Table 17.1, calculate the concentration of NH3 required to just dissolve 0.020 mol of NiC2O4 (Ksp = 4 * 10^-102) in 1.00 L of solution? (Hint: You can neglect the hydrolysis of C2O4^2- because the solution will be quite basic.)
Problem 66
- Use values of Ksp for AgI and Kf for [Ag(CN)2]- to (a) calculate the molar solubility of AgI in pure water. (b) calculate the equilibrium constant for the reaction AgI(s) + 2 CN⁻(aq) ⇌ [Ag(CN)2]⁻(aq) + I⁻(aq). (c) determine the molar solubility of AgI in a 0.100 M NaCN solution.
Problem 67
- Using the value of Ksp for Ag2S, Ka1 and Ka2 for H2S, and Kf = 1.1 * 10^5 for AgCl2^-, calculate the equilibrium constant for the following reaction: Ag2S (s) + 4 Cl^- (aq) + 2 H^+ (aq) ⇌ 2 AgCl2^- (aq) + H2S (aq)
Problem 68
- (a) Will Ca(OH)2 precipitate from solution if the pH of a 0.050 M solution of CaCl2 is adjusted to 8.0? (b) Will Ag2SO4 precipitate when 100 mL of 0.050 M AgNO3 is mixed with 10 mL of 5.0 * 10^-2 M Na2SO4 solution?
Problem 69
Problem 71
Calculate the minimum pH needed to precipitate Mn1OH22 so completely that the concentration of Mn2 +1aq2 is less than 1 mg per liter [1 part per billion (ppb)].
Problem 72
Suppose that a 10-mL sample of a solution is to be tested for I- ion by addition of 1 drop (0.2 mL) of 0.10 M Pb1NO322. What is the minimum number of grams of I- that must be present for PbI21s2 to form?
- A solution contains 2.0 * 10^-4 M Ag^+ (aq) and 1.5 * 10^-3 M Pb^2+ (aq). If NaI is added, will AgI (Ksp = 8.3 * 10^-17) or PbI2 (Ksp = 7.9 * 10^-9) precipitate first? Specify the concentration of I^- (aq) needed to begin precipitation.
Problem 73
Problem 74a
A solution of Na2SO4 is added dropwise to a solution that is 0.010 M in Ba2+(aq) and 0.010 M in Sr2+(aq). (a) What concentration of SO42- is necessary to begin precipitation? (Neglect volume changes. BaSO4: Ksp = 1.1⨉10-10; SrSO4: Ksp = 3.2⨉10-7.)
Problem 74b
A solution of Na2SO4 is added dropwise to a solution that is 0.010 M in Ba2+(aq) and 0.010 M in Sr2+(aq). (b) Which cation precipitates first?
Problem 74c
A solution of Na2SO4 is added dropwise to a solution that is 0.010 M in Ba2+(aq) and 0.010 M in Sr2+(aq). (c) What is the concentration of SO42-(aq) when the second cation begins to precipitate?
- A solution contains three anions with the following concentrations: 0.20 M CrO4^2-, 0.10 M CO3^2-, and 0.010 M Cl-. If a dilute AgNO3 solution is slowly added to the solution, what is the first compound to precipitate: Ag2CrO4 (Ksp = 1.2 * 10^-12), Ag2CO3 (Ksp = 8.1 * 10^-12), or AgCl (Ksp = 1.8 * 10^-10)?
Problem 75
- A 1.0 M Na2SO4 solution is slowly added to 10.0 mL of a solution that is 0.20 M in Ca2+ and 0.30 M in Ag+. (a) Which compound will precipitate first: CaSO4 (Ksp = 2.4 * 10^-5) or Ag2SO4 (Ksp = 1.5 * 10^-5)?
Problem 76
Problem 77
A solution containing several metal ions is treated with dilute HCl; no precipitate forms. The pH is adjusted to about 1, and H2S is bubbled through. Again, no precipitate forms. The pH of the solution is then adjusted to about 8. Again, H2S is bubbled through. This time a precipitate forms. The filtrate from this solution is treated with (NH4)2HPO4. No precipitate forms. Which of these metal cations are either possibly present or definitely absent: Al3+, Na+, Ag+, Mg2+?
Problem 79a,b
In the course of various qualitative analysis procedures, the following mixtures are encountered: (a) Zn2+ and Cd2+. (b) Cr(OH)3 and Fe(OH)3 Suggest how each mixture might be separated.
Problem 79c,d
In the course of various qualitative analysis procedures, the following mixtures are encountered: (c) Mg2+ and K+ (d) Ag+ and Mn2+. Suggest how each mixture might be separated.
Problem 80c
Suggest how the cations in each of the following solution mixtures can be separated: (c) Pb2 + and Al3 +.
Problem 81b
(b) What is the most significant difference between the sulfides precipitated in group 2 and those precipitated in group 3?
Problem 83
Which of these equations relates the pOH of a buffer to the p𝐾𝑏 of its weak base, analogous to the Henderson–Hasselbalch equation for weak acids?
a. p𝐾𝑏=pOH+p𝐾𝑏=pOH+log[acid]/[base]
b. p𝐾𝑏=pOH−log[acid]/[base]
c. p𝐾𝑏=pOH−log[base]/[acid]
d. p𝐾𝑏=pOH+log[base]/[[acid]
Problem 84
Rainwater is acidic because CO21g2 dissolves in the water, creating carbonic acid, H2CO3. If the rainwater is too acidic, it will react with limestone and seashells (which are principally made of calcium carbonate, CaCO3). Calculate the concentrations of carbonic acid, bicarbonate ion 1HCO3-2 and carbonate ion 1CO32 - 2 that are in a raindrop that has a pH of 5.60, assuming that the sum of all three species in the raindrop is 1.0 * 10-5 M.
- Furoic acid (HC5H3O3) has a Ka value of 6.76 × 10^-4 at 25 _x001F_C. Calculate the pH at 25 _x001F_C of (a) a solution formed by adding 25.0 g of furoic acid and 30.0 g of sodium furoate (NaC5H3O3) to enough water to form 0.250 L of solution; (b) a solution formed by mixing 30.0 mL of 0.250 M HC5H3O3 and 20.0 mL of 0.22 M NaC5H3O3 and diluting the total volume to 125 mL; (c) a solution prepared by adding 50.0 mL of 1.65 M NaOH solution to 0.500 L of 0.0850 M HC5H3O3.
Problem 85
Problem 86
The acid–base indicator bromcresol green is a weak acid. The yellow acid and blue base forms of the indicator are present in equal concentrations in a solution when the pH is 4.68. What is the pKa for bromcresol green?
- Equal quantities of 0.010 M solutions of an acid HA and a base B are mixed. The pH of the resulting solution is 9.2. (a) Write the chemical equation and equilibrium-constant expression for the reaction between HA and B. (b) If Ka for HA is 8.0 × 10⁻⁵, what is the value of the equilibrium constant for the reaction between HA and B?
Problem 87
Problem 88b
Two buffers are prepared by adding an equal number of moles of formic acid (HCOOH) and sodium formate (HCOONa) to enough water to make 1.00 L of solution. Buffer A is prepared using 1.00 mol each of formic acid and sodium formate. Buffer B is prepared by using 0.010 mol of each. (b) Which buffer will have the greater buffer capacity?
- A biochemist needs 750 mL of an acetic acid–sodium acetate buffer with pH 4.50. Solid sodium acetate (CH3COONa) and glacial acetic acid (CH3COOH) are available. Glacial acetic acid is 99% CH3COOH by mass and has a density of 1.05 g/mL. If the buffer is to be 0.15 M in CH3COOH, how many grams of CH3COONa and how many milliliters of glacial acetic acid must be used?
Problem 89
Problem 90a
A sample of 0.2140 g of an unknown monoprotic acid was dissolved in 25.0 mL of water and titrated with 0.0950 M NaOH. The acid required 30.0 mL of base to reach the equivalence point. (a) What is the molar mass of the acid?
Problem 91a
A sample of 0.1687 g of an unknown monoprotic acid was dissolved in 25.0 mL of water and titrated with 0.1150 M NaOH. The acid required 15.5 mL of base to reach the equivalence point. (a) What is the molar mass of the acid?
Problem 91b
A sample of 0.1687 g of an unknown monoprotic acid was dissolved in 25.0 mL of water and titrated with 0.1150 M NaOH. The acid required 15.5 mL of base to reach the equivalence point. (b) After 7.25 mL of base had been added in the titration, the pH was found to be 2.85. What is the Ka for the unknown acid?