Question

calculate the pH of the solution that is made by mixing 3.5 mL of 1.0 M Naoh and 8.2 mL of 0.1 M HCl and bringing the total volume with distilled H2O to 0.25 L

Answer 1

millimoles of base = 3.5 x 1.0 = 3.5

millimoles of acid = 8.2 x 0.1 = 0.82

millimoles of base > millimoles acid

[OH-] millimoles = 3.5 -0.82 = 2.68

[OH-] concentration = millimoles / total volume (mL)

                                 = 2.68 / 250

                                  = 0.0107 M

pOH = -log[OH-] = -log (0.0107)

pOH = 1.97

pH + pOH = 14

pH = 12.0