What ratio of NaCN to HCN is needed to prepare a pH 10.00 buffer? (K_a of HCN is 4.9 × 10^-10)

buffer 2: 50.0 mL of 0.18 M NH₃ with 5.0 mL of 0.36 M HBr.

What is the pH of a solution of 0.300 M HNO₂ containing 0.100 M NaNO₂? (K_a of HNO₂ is 4.5 × 10^–4)

What is the ratio of [A^–]/[HA] at pH 5.75? The pK_a of formic acid (methanoic acid, H–COOH) is 3.75.

How much more acetic acid (pK_a = 4.76) than acetate should be in solution to maintain a pH of 4.00?

Calculate the pH when 40.0 mL of 0.150 M KOH is mixed with 20.0 mL of 0.300 m HBrO (K_a = 2.5 × 10^-9)

Use the Henderson–Hasselbalch equation to calculate the pH of each solution in Problem 29.

Calculate the ratio of NaF to HF required to create a buffer with pH = 3.90.