AV

8.7 Acid-Base Titrations

  • Why do we perform titrations?

    • used to determine an unknown CONCENTRATION OR pH using a standing solution (solution with known concentrations).
    • Acid + Base → Salt + Water
    • Titrant: stuff in the burette.
    • Sample: stuff in the flask.
    • Equivalence point: point where neutralization is complete. [H+] = [OH-]
    • strong acids and strong bases; pH = 7 in strong/strong; [H+] = [OH-]
    • weak / strong; ph does not equal 7; [H+] does not equal [OH-] due to hydrolysis of H2O
    • Endpoint: point in a titration where an observable change occurs.

    Indicator also goes with the sample. Sample is usually an acid and the titrant a base.

<<Strong Acid, Strong Base: HNO3 (aq) + NaOH(aq) → H2O(l) + NaNO3 (aq)<<

<<HC2H3O2(aq) + NaOH(aq) → H2O(l) + NaC2H3O2(aq)<<

  • Problem 2: Determine the [H+] and pH of the solution at:

    • Before the reaction starts (pH of a weak acid)
    • At equivalence point (pH of a salt solution)
    • Beyond equivalence point (pH of a strong base)