1. Acid-Base Theories Section 20.3
Arrhenius acids: hydrogen-containing compounds that ionize to yield H+ in aqueous solution.
HCl + H2O --> H3O+ + Cl-
Arrhenius bases: compounds that ionize to yield OH- in aqueous solution
2Na + 2H2O --> NaOH + H2

2. A few terms… Monoprotic acids: contain 1 ionizable hydrogen
Nitric Acid HNO3
Diprotic acids: contain 2 ionizable hydrogens
Sulfuric Acid H2SO4
Triprotic acids: contain 3 ionizable hydrogens
Phosphoric Acid H3PO4

3. Bronsted-Lowry Acids and Bases
Acid: hydrogen-ion donor
Base: hydrogen-ion acceptor
NH3 + H2O <--> NH4+ + OH-
Hydrogen-ion Hydrogen-ion Ammonium ion
acceptor donor

4. Conjugate Acid & Base
Conjugate Acid: particle formed when a base gains a hydrogen ion
Conjugate Base: particle that remains when an acid has donated a hydrogen ion
NH3 + H2O <--> NH4+ + OH-
Base Acid Conjugate Conjugate
Acid Base
Amphoteric: substance that acts as both an acid & a base
Examples: H2O, HSO4- (Hydrogen Sulfate Ion)

5. Lewis Acid & Base
Lewis Acid: substance that can accept a pair of electrons to form a covalent bond.
Lewis Base: substance that can donate a pair of electrons to form a covalent bond.
H+ + OH- --> H2O
Lewis Lewis
Acid Base