Question

Predict whether you would expect the effect of dilution on the pH of a solution of HCl to be greater or less than that observed for a solution of acetic acid and sodium bicarbonate. Explain.

Answer 1

Note that

HCl is a STRONG acid, will dissociate into H+ and Cl- at 100%

if this is true

increase in volume will decrease [H+]

since [H+] = mol of H+ / V

note that V increases as it is diluted

so [H´+] must decrease

if [H+] decreases pH decreases

for the case ofe

acetic acid + sodium bicarbonate --> those are wek acid / bases

they will note change drastially as Volume increases.

Actually, for the sodium bicarbonate, it will remain with a pH near to the average of pKa1 and pKa2, since it does not depends directly on HCO3- concentration