Question

Ammonia (NH₃) is a weak base with a pKb of 4.75. Its conjugate acid, ammonium (NH₄⁺) has a pKa of 9.25. Set up a titration using 20.00 mL of HCL to titrate 20.00 mL of aqueous ammonia solution.

Concentration of HCl soln: 0.1044 mol/L 

Initial buret reading (mL): 0.00

Buret reading at equivalence pt (mL): 14.41

Calculate the following:

a.) Moles of HCl added at equivalence pt

b.) Moles of NH₃ in sample

c.) NH₃ concentration (mol/L)

d.) pH at equivalence point

e.) pH at half the volume required to reach equivalence