For the titration of 35.0 mL of 0.250 M NH3 with 0.500 M HCl at 25 °C, determine the relative pH at each of these points:

(a) before the addition of any HCl
(b) after 17.5 mL of HCl has been added
(c) after 37.5 mL of HCl has been added

My main issue with these kinds of problems is that I don't know how to solve this without the Ka or pKa since I can't use the Henderson-Hasselbalch equation. What is the answers for these and how do I find them?

Question

For the titration of 35.0 mL of 0.250 M NH3 with 0.500 M HCl at 25 °C, determine the relative pH at each of these points:

(a) before the addition of any HCl
(b) after 17.5 mL of HCl has been added
(c) after 37.5 mL of HCl has been added

My main issue with these kinds of problems is that I don't know how to solve this without the Ka or pKa since I can't use the Henderson-Hasselbalch equation. What is the answers for these and how do I find them?

anonymous · Answer

Nevermind figured it out. You don't even need the numbers. You just need to know that HCl is a strong acid (Very low pH) and NH3 is not a strong base (Relatively high pH, but not that high). So when you add HCl it will lower the pH very quickly because the acid is so strong. Therefore...

a) pH will be greater than 7
b) pH will be less than 7
c) pH will be less than 7