Answer to Question #172884 in General Chemistry for Charlie Del Mundo

Question

Compute for the pH of an acetate buffer produced by mixing 500 ml of a 0.5 M NaHCO3

solution and 300 ml of 0.25 M H2CO3 solution.

pka = 6.1

Answer 1

Mmol of Acid = 300×0.25 = 75 mmol

Mmol of Salt = 500×0.50 = 250 mmol

It is Acidic buffer

$pH = pKa + log(S/A)$

pH = 6.1 + log(250/75)

= [6.62]