Back
- A 15.0-mL sample of 0.100 M Ba(OH)2 is titrated with 0.125 M HCl. Calculate the pH for at least five different points throughout the titration curve and sketch the curve. Indicate the volume at the equivalence point on your graph.
Problem 7
- A 20.0-mL sample of a 0.125 M diprotic acid (H2A) solution is titrated with 0.1019 M KOH. The acid ionization constants for the acid are Ka1 = 5.2 * 10^-5 and Ka2 = 3.4 * 10^-10. At what added volume of base does each equivalence point occur?
Problem 8
- After a 120.0-mL sample of a solution that is 2.8 * 10^-3 M in AgNO3 is mixed with a 225.0-mL sample of a solution that is 0.10 M in NaCN and the solution reaches equilibrium, what concentration of Ag+(aq) remains?
Problem 11
- A 0.5224-g sample of an unknown monoprotic acid was titrated with 0.0998 M NaOH. The equivalence point of the titration occurred at 23.82 mL. Determine the molar mass of the unknown acid.
Problem 12
- Aniline, abbreviated fNH2, where f is C6H5, is an important organic base used in the manufacture of dyes. It has a Kb of 4.3 * 10^(-10). In a certain manufacturing process, it is necessary to keep the concentration of fNH3+ (aniline’s conjugate acid, the anilinium ion) below 1.0 * 10^(-9) M in a solution that is 0.10 M in aniline. Find the concentration of NaOH required for this process.
Problem 13
Problem 27
In which of these solutions will HNO2 ionize less than it does in pure water? a. 0.10 M NaCl b. 0.10 M KNO3 c. 0.10 M NaOH d. 0.10 M NaNO2
Problem 28
A formic acid solution has a pH of 3.25. Which of these substances will raise the pH of the solution upon addition? Explain your answer. a. HCl b. NaBr c. NaCHO2 d. KCl
Problem 29a
Solve an equilibrium problem (using an ICE table) to calculate the pH of each solution. a. a solution that is 0.20 M in HCHO2 and 0.15 M in NaCHO2
Problem 29b
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
Problem 30
Solve an equilibrium problem (using an ICE table) to calculate the pH of each solution. a. a solution that is 0.195 M in HC2H3O2 and 0.125 M in KC2H3O2 b. a solution that is 0.255 M in CH3NH2 and 0.135 M in CH3NH3Br
Problem 31
Calculate the percent ionization of a 0.15 M benzoic acid solution in pure water and in a solution containing 0.10 M sodium benzoate. Why does the percent ionization differ significantly in the two solutions?
- What is the percent ionization of a 0.13 M formic acid solution in pure water, and how does it compare to the percent ionization in a solution containing 0.11 M potassium formate?
Problem 32
Problem 33a
Solve an equilibrium problem (using an ICE table) to calculate the pH of each solution. a. 0.15 M HF
Problem 33b
Solve an equilibrium problem (using an ICE table) to calculate the pH of each solution. b. 0.15 M NaF
Problem 33c
Solve an equilibrium problem (using an ICE table) to calculate the pH of each solution. c. a mixture that is 0.15 M in HF and 0.15 M in NaF
Problem 34
Solve an equilibrium problem (using an ICE table) to calculate the pH of each solution. a. 0.18 M CH3NH2 b. 0.18 M CH3NH3Cl c. a mixture that is 0.18 M in CH3NH2 and 0.18 M in CH3NH3Cl
Problem 35
A buffer contains significant amounts of acetic acid and sodium acetate. Write equations showing how this buffer neutralizes added acid and added base.
Problem 36
A buffer contains significant amounts of ammonia and ammonium chloride. Write equations showing how this buffer neutralizes added acid and added base.
Problem 37
Use the Henderson–Hasselbalch equation to calculate the pH of each solution in Problem 29.
- Use the Henderson–Hasselbalch equation to calculate the pH of each solution in Problem 30.
Problem 38
Problem 39c
Use the Henderson–Hasselbalch equation to calculate the pH of each solution. c. a solution that contains 10.0 g of HC2H3O2 and 10.0 g of NaC2H3O2 in 150.0 mL of solution
Problem 41a
Calculate the pH of the solution that results from each mixture. a. 50.0 mL of 0.15 M HCHO2 with 75.0 mL of 0.13 M NaCHO2
Problem 41b
Calculate the pH of the solution that results from each mixture. b. 125.0 mL of 0.10 M NH3 with 250.0 mL of 0.10 M NH4Cl
Problem 42
Calculate the pH of the solution that results from each mixture. a. 150.0 mL of 0.25 M HF with 225.0 mL of 0.30 M NaF b. 175.0 mL of 0.10 M C2H5NH2 with 275.0 mL of 0.20 M C2H5NH3Cl
Problem 43
Calculate the ratio of NaF to HF required to create a buffer with pH = 4.00.
Problem 44
Calculate the ratio of CH3NH2 to CH3NH3Cl concentration required to create a buffer with pH = 10.24.
Problem 45
What mass of sodium benzoate should you add to 150.0 mL of a 0.15 M benzoic acid solution to obtain a buffer with a pH of 4.25? (Assume no volume change.)
Problem 46
Pick the stronger base from each pair. a. ClO4– or ClO2– b. Cl– or H2O c. CN– or ClO–
- What mass of ammonium chloride should be added to 2.55 L of 0.155 M NH3 to obtain a buffer with a pH of 9.55? (Assume no volume change.)
Problem 46
- A 250.0-mL buffer solution is 0.250 M in acetic acid and 0.250 M in sodium acetate. a. What is the initial pH of this solution? b. What is the pH after the addition of 0.0050 mol of HCl? c. What is the pH after the addition of 0.0050 mol of NaOH?
Problem 47