1. 8.4 Acid-Base Theories

2. Recall: Arrhenius’ TheoryAcids:  Arrhenius theory  Arrhenius theory: Any substance that, when dissolved in water, increases the concentration of hydrogen ion (H + )Bases:  Arrhenius theory  Arrhenius theory: Any substance that, when dissolved in water, increases the concentration of hydroxide ion (OH - )

3. Lone Hydrogen ions do not exist by themselves in solution. H+ is always bound to a water molecule to form a hydronium ion

4. The Bronsted-Lowry ConceptAcids:  Arrhenius theory  Arrhenius theory: Any substance that, when dissolved in water, increases the concentration of hydrogen ion (H + )  Bronsted-Lowry concept  Bronsted-Lowry concept: A proton donor or sourceBases:  Arrhenius theory  Arrhenius theory: Any substance that, when dissolved in water, increases the concentration of hydroxide ion (OH - )  Bronsted-Lowry concept  Bronsted-Lowry concept: A proton acceptor or receiver

5. Brønsted-Lowry Theory of Acids & Bases General Equation

6. Brønsted-Lowry Theory of Acids & Bases

8. Notice that water is both an acid & a base = amphoteric Reversible reaction

9. Conjugate Acid-Base Pairs

11. Acids & Bases CB For the following Identify the conjugate acid and the conjugate base. The conjugate refers to the acid or base produced in an acid/base reaction. The acid reactant produces its conjugate base (CB). a. Al(OH) 3 + 3 HCl  AlCl 3 + 3 H 2 O b. Ba(OH) 2 + 2 HC 2 H 3 O 2  Ba(C 2 H 3 O 2 ) 2 + 2 H 2 O c. 2 KOH + H 2 SO 4  K 2 SO 4 + 2 H 2 O d. NH 3 + H 2 O  NH 4 + + OH - CB CA CA CB

12. Homework “Conjugate Acid Base Pairs” Worksheet