Question

Which of the following would be the best choice for preparing a buffer with a pH = 8.0? Group of answer choices a solution of boric acid and sodium borate, Ka = 5.8 × 10^–10 a solution of hypochlorous acid and sodium hypochlorite, Ka = 3.5 × 10^–8 a solution of formic acid and sodium formate, Ka = 1.8 × 10^–4 All of these solutions would be equally good choices for making this b

Answer 1

Answer:

Hypochlorous acid - Sodium hypochlorite

Explanation:

A buffer works when pH you want is ± 1 unit of pKa of the buffer. For example, for a buffer with pKa 7, it works between 6 and 8 (7-1 and 7+1).

pKa = -log Ka:

pKa boric acid - Sodium borate: 9.23. As you want a pH of 8.0. This buffer has a pKa too high.

pKa Hypochlorous acid - Sodium hypochlorite: 7.46. With this pKa, this buffer is a great choice to prepare it with a pH = 8.0

pKa Formic acid - Sodium formate: 3.74. This pKa is too low to make a buffer with pH = 8.0

Best choice is:

Hypochlorous acid - Sodium hypochlorite