Preparing Buffers

The following may be useful.

 1) Which of the following buffers would work best for an experiment requiring a pH of 6.5?

     (a) 0.60 mol H₂S / 0.19 mol HS^-

     (b) 0.19 mol H₂S / 0.60 mol HS^-

     (c) 0.20 mol HCO₃^- / 0.15 mol H₂CO₃

     (d) 0.15 mol HCO₃^- / 0.20 mol H₂CO₃

 2) Which of the following buffers would work best for an experiment requiring a pH of 7.8?

     (a) 0.22 mol HClO / 0.10 mol ClO^-

     (b) 0.10 mol HClO / 0.22 mol ClO^-

     (c) 0.19 mol HSO₃^- / 0.05 mol SO₃^2-

     (d) 0.05 mol HSO₃^- / 0.19 mol SO₃^2-

 3) Which of the following acid-base pairs would work best for an experiment requiring a pH of 9.0?

     (a) 0.056 mol NH₄⁺ / 0.10 mol NH₃

     (b) 0.10 mol NH₄⁺ / 0.056 mol NH₃

     (c) 0.10 mol B(OH)₃(H₂O) / 0.072 mol B(OH)₄^-

     (d) 0.072 mol B(OH)₃(H₂O) / 0.10 mol B(OH)₄^-

 4) Which of the following acid-base pairs would work best for an experiment requiring a pH of 3.5?

     (a) 0.10 mol formic acid / 0.056 mol formate ion

     (b) 0.056 mol formic acid / 0.10 mol formate ion

     (c) 0.10 mol lactic acid / 0.045 mol lactate ion

     (d) 0.045 mol lactic acid / 0.10 mol lactate ion

 5) Which of the following buffering systems would work best for an experiment requiring a pH of 1.8?

     (a) 0.32 mol H₃PO₄ / 0.15 mol H₂PO₄^-

     (b) 0.15 mol H₃PO₄ / 0.32 mol H₂PO₄^-

     (c) 0.20 mol H₂SO₃ / 0.15 mol HSO₃^-

     (d) 0.15 mol H₂SO₃ / 0.20 mol HSO₃^-

 6) Which of the following buffering systems would work best for an experiment requiring a pH of 2.4?

     (a) 0.57 mol H₃PO₄ / 0.30 mol H₂PO₄^-

     (b) 0.30 mol H₃PO₄ / 0.57 mol H₂PO₄^-

     (c) 0.11 mol HF / 0.60 mol F^-

     (d) 0.60 mol HF / 0.11 mol F^-

 7) Which of the following buffering systems would work best for an experiment requiring a pH of 3.0?

     (a) 0.11 mol HNO₂ / 0.60 mol NO₂^-

     (b) 0.60 mol HNO₂ / 0.11 mol NO₂^-

     (c) 0.15 mol HF / 0.20 mol F^-

     (d) 0.20 mol HF / 0.15 mol F^-

 8) Which of the following acid-base pairs would work best for an experiment requiring a pH of 3.4?

     (a) 0.45 mol HNO₂ / 0.50 mol NO₂^-

     (b) 0.50 mol HNO₂ / 0.45 mol NO₂^-

     (c) 0.30 mol HF / 0.55 mol F^-

     (d) 0.55 mol HF / 0.30 mol F^-

 9) Which of the following buffering systems would work best for an experiment requiring a pH of 3.9?

     (a) 0.80 mol CH₃CO₂H / 0.12 mol CH₃CO₂^-

     (b) 0.12 mol CH₃CO₂H / 0.80 mol CH₃CO₂^-

     (c) 0.15 mol HCO₂H / 0.22 mol HCO₂^-

     (d) 0.22 mol HCO₂H / 0.15 mol HCO₂^-

10) Which of the following buffering systems would work best for an experiment requiring a pH of 4.9?

      (a) 0.40 mol CH₃CH₂CO₂H / 0.36 mol CH₃CH₂CO₂^-

      (b) 0.36 mol CH₃CH₂CO₂H / 0.40 mol CH₃CH₂CO₂^-

      (c) 0.35 mol CH₃CO₂H / 0.24 mol CH₃CO₂^-

      (d) 0.24 mol CH₃CO₂H / 0.35 mol CH₃CO₂^-

11) Which of the following acid-base pairs would work best for an experiment requiring a pH of 6.9?

      (a) 0.25 mol H₂PO₄^- / 0.50 mol HPO₄^-2

      (b) 0.50 mol H₂PO₄^- / 0.25 mol HPO₄^-2

      (c) 0.10 mol H₂S / 0.13 mol HS^-

      (d) 0.13 mol H₂S / 0.10 mol HS^-

12) Which of the following acid-base pairs would work best for an experiment requiring a pH of 7.3?

      (a) 0.25 mol H₂PO₄^- / 0.31 mol HPO₄^-2

      (b) 0.31 mol H₂PO₄^- / 0.25 mol HPO₄^-2

      (c) 0.20 mol HClO / 0.13 mol ClO^-

      (d) 0.13 mol HClO / 0.30 mol ClO^-

13) Which of the following buffering systems would work best for an experiment requiring a pH of 9.1?

      (a) 0.25 mol HCN / 0.13 mol CN^-

      (b) 0.13 mol HCN / 0.25 mol CN^-

      (c) 0.43 mol NH₄⁺/ 0.30 mol NH₃

      (d) 0.30 mol NH₄⁺/ 0.43 mol NH₃

14) Which of the following buffering systems would work best for an experiment requiring a pH 9.6?

      (a) 0.17 mol Fe(H₂O)₆⁺² / 0.13 mol Fe(H₂O)₅OH⁺

      (b) 0.13 mol Fe(H₂O)₆⁺² / 0.17 mol Fe(H₂O)₅OH⁺

      (c) 0.27 mol HCN / 0.17 mol CN^-

      (d) 0.17 mol HCN / 0.27 mol CN^-

15) Which of the following acid-base pairs would work best for an experiment requiring a pH of 7.4?

      (a) 0.50 mol H₂S / 0.20 mol HS^-

      (a) 0.20 mol H₂S / 0.50 mol HS^-

      (a) 0.16 mol HSO₃^- / 0.10 mol SO₃^-2

      (a) 0.10 mol HSO₃^- / 0.16 mol SO₃^-2

16) Which of the following acid-base pairs would work best for an experiment requiring a pH of 10.4?

      (a) 0.14 mol HCO₃^- / 0.17 mol CO₃^-2

      (b) 0.17 mol HCO₃^- / 0.14 mol CO₃^-2

      (c) 0.40 mol Ni(H₂O)₆⁺² / 0.25 mol Ni(H₂O)₅OH⁺

      (d) 0.25 mol Ni(H₂O)₆⁺² / 0.40 mol Ni(H₂O)₅OH⁺

17) Which of the following buffering systemswould work best for an experiment requiring a pH of 10.5?

      (a) 0.20 mol HCO₃^- / 0.30 mol CO₃^-

      (b) 0.30 mol HCO₃^- / 0.20 mol CO₃^-

      (c) 0.25 mol Ni(H₂O)₆⁺² / 0.20 mol Ni(H₂O)₅OH⁺

      (d) 0.20 mol Ni(H₂O)₆⁺² / 0.25 mol Ni(H₂O)₅OH⁺

18) Which of the following buffering systems would work best for an experiment requiring a pH 4.0?

      (a) 0.16 mol CH₃CHOHCOOH / 0.11 mol CH₃CHOHCOO^-

      (b) 0.11 mol CH₃CHOHCOOH / 0.16 mol CH₃CHOHCOO^-

      (c) 0.23 mol CH₃COOH / 0.50 mol CH₃COO^-

      (d) 0.50 mol CH₃COOH / 0.23 mol CH₃COO^-

19) Which of the following acid-base pairs would work best for a reaction requiring a pH of 4.6?

      (a) 0.10 mol CH₃CH₂COOH / 0.18 mol CH₃CH₂COO^-

      (b) 0.18 mol CH₃CH₂COOH / 0.10 mol CH₃CH₂COO^-

      (c) 0.20 mol CH₃COOH / 0.28 mol CH₃COO^-

      (d) 0.28 mol CH₃COOH / 0.20 mol CH₃COO^-

20) Which of the following acid-base pairs would work best for an experiment requiring a pH of 6.8?

      (a) 0.20 mol H₂S / 0.13 mol HS^-

      (b) 0.13 mol H₂S / 0.20 mol HS^-

      (c) 0.10 mol HCO₃^- / 0.26 mol CO₃^-2

      (d) 0.26 mol HCO₃^- / 0.10 mol CO₃^-2