1. ACID-BASE THEORY

2. Arrhenius Acids and Bases
Acids dissociate in water to give H+ ions.
Bases dissociate in water to give OH- ions.
Strong acids and bases are 100% dissociated.
HI(aq) H+(aq) + I- (aq)

3. the only recognized type
BRONSTED - LOWRY THEORY
conjugate
base
conjugate
acid
acid
base
HA B A BH
lose H+
gain H+
acid = proton (H+) donor
Everything is defined
in terms of the proton,
the only recognized type
of acid in B-L theory.
base = proton (H+) acceptor

4. Figure: UN
Caption:
In addition to the Arrhenius acids and bases, the Brønsted–Lowry definition includes bases that have no hydroxide ions, yet can accept protons. Consider the following examples of acids donating protons to bases. NaOH is a base under either the Arrhenius or Brønsted–Lowry definition. The other three bases are included under the Brønsted–Lowry definition but not under the Arrhenius definition because they have no hydroxide ions.

5. Na2CO3(aq) + 2HCl(aq)  H2CO3(aq) + 2NaCl(aq)
Conjugate acids and Conjugate bases
HCl(aq) + KOH(aq) 
HOH(aq) KCl(aq)
acid
base
conj. acid
conj. base
Na2CO3(aq) HCl(aq)  H2CO3(aq) NaCl(aq)
base
acid
conj. acid
conj. base
Na2CO3(aq) HCl(aq)  H2O(l) + CO2(g) + 2NaCl(aq)
acid
base
conj. acid
conj. base

6. Acid and Base Strength
Strong acids and bases completely dissociate in water
Weak acids and bases partially dissociate in water
Acid dissociation constant Ka
larger Ka = stronger weak acid
Base dissociation constant Kb
larger Kb = stronger weak base
stronger acid = weaker conjugate base
weaker acid = stronger conjugate base

7. 100% ionized (completely dissociated) in water. HCl  H+ + Cl-
Strong Acids:
100% ionized (completely dissociated) in water.
HCl  H+ + Cl-
Strong Acids:
Perchloric HClO4
Chloric HClO3
Hydrobromic HBr
Hydrochloric HCl
Hydroiodic HI
Nitric HNO3
Sulfuric H2SO4

8. 100% ionized (completely dissociated) in water.
Strong Bases:
100% ionized (completely dissociated) in water.
Strong Bases:
alkali and heavy alkaline earth hydroxides
LiOH, NaOH, KOH, RbOH, and CsOH
Ca(OH)2, Sr(OH)2, and Ba(OH)2

9. Ba(OH)2(aq) H3PO4(aq) 
Ba(OH)2(aq) H3PO4(aq) 
Ba3(PO4)2(aq) + H2O(l)
Ba3(PO4)2(aq) + 6H2O(l)
HC2H3O2(aq) NaOH(aq) 
NaC2H3O2(aq) + H2O(l)
H2SO4(aq) KOH(aq) 
H2SO4(aq) KOH(aq) 
K2SO4(aq) + 2H2O(l)
K2SO4(aq) + H2O(l)
H2CO3(aq) NaOH(aq) 
H2CO3(aq) NaOH(aq) 
Na2CO3(aq) + 2H2O(l)
Na2CO3(aq) + H2O(l)

10. Strong Acids:
100% ionized (completely dissociated) in water.
HCl  H+ + Cl-
Note the “one way arrow”.
Weak Acids:
Only a small % dissociated in water.
HC2H3O2 ⇆ H+ + C2H3O2-
Note the “2-way” arrow.

11. electron-pair acceptor
LEWIS ACID - BASE THEORY
more general than Bronsted - Lowery theory
BASE
Substances other
than proton donor
and acceptors are
recognized as
acids and bases. B:
electron-pair donor A
ACID
electron-pair acceptor
Lewis
base
Lewis
acid

12. Lewis base Lewis acid Figure: 01-07-055UN Caption:
The Lewis acid–-base definitions allow reactions having nothing to do with protons to be considered as acid–base reactions. Below are some examples of Lewis acid–base reactions. Notice that the common Brønsted–-Lowry acids and bases also fall under the Lewis definition, with a proton serving as the electrophile. Curved arrows are used to show the movement of electrons, generally from the nucleophile to the electrophile.
Lewis
base
Lewis
acid