Titrating Polyfunctional
Acids and Bases
1. Treating Complex Acid-Base Systems
• Complex systems are defined as solutions
made up of:
(1) An acid or base that has two or more
acidic protons or basic functional groups
H3PO4
Ca(OH)2
(2) Two acids or bases of different strengths
HCl + CH3COOH
NaOH + CH3COO-
3) An amphiprotic substance that is capable
of acting as both acid and base
HCO3- + H2O <=> CO32- + H3O+
HCO3- + H2O <=> H2CO3 + OHNH3+CH2COO- + H2O <=> NH2CH2COO- + H3O+
NH3+CH2COO- + H2O <=> NH3+CH2COOH + OH-
Problems
1. Understanding Ka1>Ka2>Ka3…
2. The relationship between Ka and Kb of
its conjugate base.
Example 13-1, 2, 3
1. Calculate the hydronium ion concentration of
0.100M NaHCO3 solution.
2. Calculate the hydronium ion concentration of
1.00×10-3M Na2HPO4 solution.
3. Find the hydronium ion concentration of
0.0100M NaH2PO4 solution.
Mixtures of Strong and Weak Acids
Mixtures of Strong and Weak bases?
Problem(P325, 13-25): Identify by letter the curve you would expect in
the titration of a solution containing
(a) disodium maleate, Na2M, with standard acid (1.3x10-2, 5.9x10-7)
(b) pyruvic acid, HP, with standard base (3.2x10-3)
(c) sodium carbonate, Na2CO3, with standard acid (1.5x10-4, 4.69x10-11)