1. Titration of Strong Monoprotic Acid and Base

2. Polyprotic Acids How to solve K a expression for Polyprotic Acids?

3. Polyprotic Acids/Bases Bethany Storro polyprotic acid can donate more than one proton polyprotic base can accept more than one proton H 2 SO 4 Ba(OH) 2

4. Equilibrium Expressions for Polyprotics K a1 = ionization constant for the first hydrogen atom H 2 S(aq) + H 2 O(l)   H 3 O + (aq) + HS - (aq) K a2 = ionization constant for the second hydrogen atom HS - (aq) + H 2 O(l)   H 3 O + (aq) + S 2- (aq)

5. K a1 compared to K a2 If the difference between the K a1 and the K a2 values is 10 3 or more, the pH generally depends only on the first dissociation.

6. Unique among common acids STRONG in is first dissociation step ( ≥1.0 M) WEAK acid in the second step (use quadratic) H 2 SO 4

7. Typical Titration with Weak Monoprotic Acids

8. Do the Structure, Initial Concentration of A/B influence pH ? Investigate your designated question Design a series of investigations involving titrations Analyze titration curves Pool data/Compare data with others Answer primary question of lab

9. Available Materials 0.2 M HCl 0.1 M H 2 SO 4 0.05 M HNO 3 0.1 M HC 2 H 3 O 2 0.2 M NH 3 0.1 M NaOH 0.1 M Ca(OH) 2 Stir rod 2 x 100 mL grad. cylinders 2 x 250 flasks Ring pH strips, probe 2 x 50 mL burets + clamp