Consider the titration of 50 mL of 0.250 M HCl with 0.1250 M NaOH. Calculate the pH of the resulting solution after the following volumes of Na OH have been added.

Question

a) 0.00 mL
b) 50.00 mL
c) 99.90 mL
d) 100.00 mL
e) 100.1 mL

The question is, I get, for example, 0.9 pH for "a." However, where I am getting the molarity to do this is from the NaOH solution. Am I right? If not, from which solution should I get the molarity from?

Answer 1

For a. You have 0.00 mL of NaOH; therefore the pH will be determined solely by HCl.
pH = -log(0.250)
pH = 0.602