pH and stoichiometric point!?

Question

100.0 mL of a solution of quinine contains 170.0 x 10-3 mol of quinine.
a) If this is titrated with 0.200 M HCl, what is the pH half-way to the stoichiometric point ?

Quinine is monobasic with Kb = 7.90 x 10-6

b) What is the pH at the stoichiometric point ?

Answer 1

100.0 ml is also equal to 100.0 cubic-centimeters;
170.0x10-3 is = stoichiometric point 1.7 x10-1

0.200 M HCL = 2.0 x10-1 M HCL

Quinine 7.9 x 10-6 pH half-way to the stoichiometric point would be 0.0079 x 10-3

Answer 2

half way sto. point would be [Q]=[QH+]..making it 1.
[H3O+] = -log Ka + log [base]/[acid]
since [base]/[acid] is 1..then
[H3O+] = -log Ka