ch 17 first 87

19) A 1.00 L buffer solution is 0.250 M in HF and 0.250 M in NaF. Calculate the pH of the solution after the addition of 100.0 mL of 1.00 M HCl. The Ka for HF is 3.5 × 10-4. A) 3.09 B) 4.11 C) 3.82 D) 3.46 E) 2.78

A) 3.09

12) Calculate the pH of a solution formed by mixing 250.0 mL of 0.15 M NH4Cl with 200.0 mL of 0.12 M NH3. The Kb for NH3 is 1.8 × 10-5. A) 9.06 B) 9.45 C) 4.55 D) 4.74 E) 9.26

A) 9.06

5) If the pKa of HCHO2 is 3.74 and the pH of an HCHO2/NaCHO2 solution is 3.89, which of the following is TRUE? A) [HCHO2] < [NaCHO2] B) [HCHO2] = [NaCHO2] C) [HCHO2] > [NaCHO2] D) [HCHO2] >> [NaCHO2] E) It is not possible to make a buffer of this pH from HCHO2 and NaCHO2.

A) [HCHO2] < [NaCHO2]

1) Animals will lick up ethylene glycol (antifreeze) due to its sweet taste. The antidote for ethylene glycol poisoning is the administration of A) ethyl alcohol ( alcoholic drinks). B) isopropyl alcohol (rubbing alcohol). C) mineral oil (laxative). D) vinegar. E) sodium bicarbonate (baking soda).

A) ethyl alcohol ( alcoholic drinks).

20) A 1.00 L buffer solution is 0.250 M in HF and 0.250 M in LiF. Calculate the pH of the solution after the addition of 0.150 moles of solid LiOH. Assume no volume change upon the addition of base. The Ka for HF is 3.5 × 10-4. A) 3.46 B) 4.06 C) 2.85 D) 3.63 E) 4.24

B) 4.06

13) Calculate the pH of a solution formed by mixing 100.0 mL of 0.20 M HClO with 200.0 mL of 0.30 M KClO. The Ka for HClO is 2.9 × 10-8. A) 5.99 B) 8.01 C) 7.54 D) 7.06 E) 6.46

B) 8.01

10) Calculate the pH of a buffer that is 0.200 M H3BO3 and 0.122 M KH2BO3. The Ka for H3BO3 is 5.8 × 10-10. A) 8.93 B) 9.02 C) 10.77 D) 9.46 E) 3.52

B) 9.02

7) If a chemist wishes to prepare a buffer that will be effective at a pH of 3.00 at 25°C, the best choice would be an acid component with a Ka equal to A) 9.10 × 10-2. B) 9.10 × 10-4. C) 9.10 × 10-6. D) 9.10 × 10-8. E) 9.10 × 10-10.

B) 9.10 × 10-4.

6) If the pKa of HCHO2 is 3.74 and the pH of an HCHO2/NaCHO2 solution is 3.74, which of the following is TRUE? A) [HCHO2] > [NaCHO2] B) [HCHO2] = [NaCHO2] C) [HCHO2] < [NaCHO2] D) [HCHO2] < <[NaCHO2] E) It is not possible to make a buffer of this pH from HCHO2 and NaCHO2.

B) [HCHO2] = [NaCHO2]

16) Calculate the pH of a solution formed by mixing 150.0 mL of 0.10 M HC7H5O2 with 100.0 mL of 0.30 M NaC7H5O2. The Ka for HC7H5O2 is 6.5 × 10-5. A) 4.19 B) 9.69 C) 4.49 D) 4.31 E) 10.51

C) 4.49

15) Calculate the pH of a solution formed by mixing 200.0 mL of 0.30 M HClO with 300.0 mL of 0.20 M KClO. The Ka for HClO is 2.9 × 10-8. A) 5.99 B) 8.01 C) 7.54 D) 7.06 E) 6.46

C) 7.54

8) Calculate the pH of a solution formed by mixing 250.0 mL of 0.900 M NH4Cl with 250.0 mL of 1.60 M NH3. The Kb for NH3 is 1.8 × 10-5. A) 8.25 B) 9.18 C) 9.50 D) 10.12 E) 10.83

C) 9.50

2) An important buffer in the blood is a mixture of A) sodium chloride and hydrochloric acid. B) hydrochloric acid and sodium hydroxide. C) carbonic acid and bicarbonate ion. D) acetic acid and bicarbonate ion. E) acetic acid and carbonate ion.

C) carbonic acid and bicarbonate ion.

17) Calculate the pH of a solution formed by mixing 250.0 mL of 0.15 M HCHO2 with 100.0 mL of 0.20 M LiCHO2. The Ka for HCHO2 is 1.8 × 10-4. A) 3.87 B) 3.74 C) 10.53 D) 3.47 E) 10.13

D) 3.47

14) Calculate the pH of a solution formed by mixing 200.0 mL of 0.30 M HClO with 100.0 mL of 0.20 M KClO. The Ka for HClO is 2.9 × 10-8. A) 5.99 B) 8.01 C) 7.54 D) 7.06 E) 6.46

D) 7.06

4) If the pKa of HCHO2 is 3.74 and the pH of an HCHO2/NaCHO2 solution is 3.11, which of the following is TRUE? A) [HCHO2] < [NaCHO2] B) [HCHO2] = [NaCHO2] C) [HCHO2] << [NaCHO2] D) [HCHO2] > [NaCHO2] E) It is not possible to make a buffer of this pH from HCHO2 and NaCHO2.

D) [HCHO2] > [NaCHO2]

18) A 1.00 L buffer solution is 0.150 M in HC7H5O2 and 0.250 M in LiC7H5O2. Calculate the pH of the solution after the addition of 100.0 mL of 1.00 M HCl. The Ka for HC7H5O2 is 6.5 × 10-5. A) 4.19 B) 5.03 C) 4.41 D) 3.34 E) 3.97

E) 3.97

9) Calculate the pH of a buffer that is 0.225 M HC2H3O2 and 0.162 M KC2H3O2. The Ka for HC2H3O2 is 1.8 × 10-5. A) 4.89 B) 9.11 C) 4.74 D) 9.26 E) 4.60

E) 4.60

11) Calculate the pH of a solution formed by mixing 250.0 mL of 0.15 M NH4Cl with 100.0 mL of 0.20 M NH3. The Kb for NH3 is 1.8 × 10-5. A) 9.13 B) 9.25 C) 9.53 D) 4.74 E) 8.98

E) 8.98

3) Identify a good buffer. A) small amounts of both a weak acid and its conjugate base B) significant amounts of both a strong acid and a strong base C) small amounts of both a strong acid and a strong base D) significant amounts of both a weak acid and a strong acid E) significant amounts of both a weak acid and its conjugate base

E) significant amounts of both a weak acid and its conjugate base