1. The problem statement, all variables and given/known data For the titration of 50 mL of 0.150 M ethylamine (C2H5NH2), with 0.100 M HCl, find the pH : a) when 10 mL more of HCl has been added than is required b) when 75% of the required acid has been added 2. Relevant equations Maybe Henderson Hasselbalch?: pH = pKa + log (base/acid) Ka = 2.34*10^-4 3. The attempt at a solution I honestly do not know where to go with this.