1. IV.13. HYDROLYSIS
(Hebden p. 144 – 148)

2. Hydrolysis of a Salt
Rx between water and cation &/or anion in salt that produces an acidic or basic solution
All salts are 100% ionized in water

3. Spectator Ions Do NOT react with water
The conjugates of STRONG acids and bases

4. Spectator Cations Alkali metals Alkaline earth metals
Ex: NaOH  Na+ + OH-

5. Spectator Anions
1st top of Acid/ Base Table (not HSO4- b/c it is a weak acid)
Ex: HCl  H+ + Cl-

6. To determine the behavior of salt in water…
Determine ions
Discard spectators
Remaining ions are acids if on acid side of table or bases if on base side of table

7. Ex #1: NaCl Na+ + Cl- Both Na+ and Cl- are spectators
Therefore, solution is NEUTRAL

8. 2. NH4Cl  NH4+ + Cl- Cl- is a spectator Solution is acidic
NH4+ + H2O = H3O+ + NH3

9. 3. NaF  Na+ + F- Na+ is a spectator Solution is basic
F- + H20 = HF + OH-

10. 4. NaHC2O4  Na++HC2O4-
Na+ is a spectator
Solution either acidic or basic b/c HC2O4- is amphiprotic
We must determine which rx is predominant

11. Ka for HC2O4- = 6.4 x 10-5
Kb = Kw /Ka
= 1.00 x / 5.9 x 10-2
= 1.7 x 10-13
Ka > Kb so solution is acidic
HC2O4- + H20 = H3O+ +C2O42-

12. Must determine predominant rx
5. NH4NO2  NH4+ + NO2-
No spectators
Must determine predominant rx

13. Ka of NH4+ = 5.6 x 10-10
Kb of NO2- = Kw/Ka
= 1.0 x / 4.6 x 10-4
= 2.2 x 10-11
Solution is acidic
NH4+ + H20 = H3O+ + NH3