Question

What is the theoretical pH of 0.10 M Acetic Acid with the addition of HCl? 1.00 ml of 1.0 M Hcl was added to the acetic acid solution. calculate the molarities of the acetic acid and hcl in the 51.0ml solution and calculate the theoretical pH of the solution.

Answer 1

Solution :-

New molarities of the acetic acid and HCl are calculated as follows using the initial concentration and volume and final volume.

New molarity of the acetic acid = 0.10 M * 5 ml / 51 ml = 0.0098 M

New molarity of HCl = 1.0 M * 1 ml / 51 ml = 0.0196 M

HCl is the strong acid which dissociate 100 % so the concentration of the H+ = 0.0196 M

Since the acetic acid is weak acid and also strong acid HCl is added therefore the dissociation of the acetic acid will be very less so do not consider the concentration of the H+ from acetic acid

So the theoretical pH of the solution is as follows

pH= -log [H+]

    = -log [0.0196]

    = 1.71