Question

Which of the following acid/base pairs would be best for making a buffer with a pH of 8.00?

1.Acid Formula Ka1 Ka2 Ka3 Acetic acid CH3COOH 1.8×10-5
2.Ascorbic acid H2C6H6O6 7.9×10-5 1.6×10-12
3.Carbonic acid H2CO3 4.2×10-7 4.8×10-11
4.Hydrocyanic acid HCN 4.0×10-10
5.Hydrofluoric acid HF 7.2×10-4
6.Hypochlorous acid HClO 3.5×10-8
7.Phosphoric acid H3PO4 7.5×10-3 6.2×10-8 4.8×10-13
8.Sulfurous acid H2SO3 1.7×10-2 6.4×10-8

Answer 1

Answer:

7. Phosphoric acid H₃PO₄ 7.5×10⁻³ 6.2×10⁻⁸ 4.8×10⁻¹³

3. Carbonic acid H₂CO₃ 4.2×10⁻⁷ 4.8×10⁻¹¹

Explanation:

Their blend will result to the closest pH of 8.00