12. For the strong acid-weak base titration of ammonia by hydrochloric acid, find the pH after 15.0 mL of 0.100 M HCl has been added to 25.0 mL of 0.100 M NH3 solution. (Kb = 1.8 x 10-5)

The reaction we will use is:

NH3 (aq) + H+ (aq) NH4+ (aq)

For the stoichiometric calculation:

NH3 (aq) H+ (aq) NH4+ (aq)
INITIAL
0.0025mol
0.0015mol
0mol
CHANGE
FINAL

What are the changes in number of moles for each species?

a) -x mol, -x mol, -x mol
b) -0.0015mol, -0.0015mol, +0.0015mol
c) -0.0025mol, -0.0015mol, +0.0015mol
d) -0.0025mol, -0.0025mol, +0.0025mol