15. A student is performing a titration on a solution of HNO3 with an unknown concentration. They use a solution of KOH that they determined the concentration to be 6.3 x 10-4 M beforehand. They use an aliquot of 20.0 mL of HNO3 to titrate. a. If the equivalence point is reached after the addition of 16.5 mL of titrant, what was the original pH of the analyte?

b. What would the pH of the analyte be at the equivalence point? Equation (1 mark) [C], (2 mark) calculation [T/I]

c. If the student over-titrates the analyte and adds 23.0 mL of titrant, what would the pH of the analyte be? (2 mark) calculation [T/I]

d. If the student under-titrates and only adds 8.0 mL of titrant, what is the pH of the analyte? (2 mark) calculation [T/I]