Question

Calculate the equivalence point in the titration of 9.96 mL of 0.1088 M sodium nitrophenylate with 0.106 M HCl. pKa is 7.15 for nitrophenol.

Answer 1

Number of moles of sodium nitrophenylate = 0.1088 mol/L)x0.00996 L

                                                                       = 0.001083 mol

Number of moles of HCl = 0.106 moles/1 L

At the equivalence point, the number of moles of HCl added is equal to the initial number of moles of nitrophenol, because the analyte is completely neutralized.

[(0.001083 mol)x1L]/0.106 mol = 0.0102 L = 10.2 mL

Equivalence point = 10.2 mL