Question

Determine each of the following for a 0.130 M HBr solution:

a)Calculate the volume, in milliliters, of HBr solution required to neutralize 46.0 mL of a 0.350 M LiOH solution .

Acetic acid has a Ka of 1.8×10⁻⁵.

b)What is the pH of a buffer solution containing 0.10 M HC2H3O2 (acetic acid) and 0.12 M C2H3O2−?

Answer 1

2) pKa= -log Ka = -log (1.8*10^-5) = 4.74

Use the Henderson - Hasselbalch equation:

pH = pKa + log ([CH3COO-] /[CH3COOH]

It contain 0.10 M CH3COOH and 0.12 M CH3COO–.

So [CH3COOH]=0.10 and [CH3COO–]=0.12

pH = 4.74 + log (0.12/0.10)

pH = 4.74 + log 1.2

pH = 4.74 + 0.0791

pH = 4.819