We’re being asked to calculate the pH of a solution after the addition of 40 mL 0.100 M HCl solution. The solution is made up of 25.00 mL of 0.125 M pyridine (C5H5N).
HCl (strong acid) will react with C5H5N (base).
▪ C5H5N is a weak base and based on Bronsted-Lowry definition it is a proton acceptor.
▪ HCl is a strong acid and based on Bronsted-Lowry definition it is a proton donor.
C5H5N(aq) + HCl(aq) → C5H5NH+(aq) + Cl-(aq)
We will calculate the pH of the solution using the following steps:
A 25.0-mL sample of 0.125 M pyridine is titrated with 0.100 M HCl.
Calculate the pH at 40 mL of added acid.