Question

Constants | Periodic Table Learning Goal: To calculate the pH at the equivalence point for various types of titrations. The equivalence point in an acid-base titration is the point at which stoichiometrically equivalent quantities of acid and base have been mixed together. At this point the reaction is complete because all analyte has been consumed by titrant. On a titration curve, the equivalence point is represented hv the noint of inflection (where the curve changes ring Figure 1o1 12 10 8 - Equivalence point 2 0 20.040.060.0 80.0 mL of 0.100 M NaOH added

Answer 1

Part A pH is equal to 7 for the titration of strong acid and strong base pH is less than 7 for the titration of strong acid and weak base pH is more than 7 for the titration of weak acid and strong base Part - B Number of moles of HBr (strong acid) = M*V = 0.25 M*56.0 mL = 14 mmol Number of moles of KOH (strong base) = M*V = 0.50 M*28.0 mL = 14 mmol Since the number of moles of strong acid and strong base are equal, this is the equivalence point. The pH of the solution is 7 Part C Number of moles of NH_3 = M*V = 0.20 M* 50.0 mL = 10 mmol Number of moles of HNO_3 = M*V = 0.02 M * 50.0 mL = 10 mmol This is equivalence point. At this point, there is no NH_3 is present in the solution. So the pH of the solution is determined by