1. Acid – Base Theory

2. Definitions:
Arrhenius:
An acid is a substance that increases the H+ (or H3O+) concentration in an aqueous solution.
HCl + H 2O  H3O+ + Cl-
HCl  H+ + Cl-
A base is a substance that increases the OH- concentration
in an aqueous solution.
NaOH(s)  Na+ + OH-

3. Produce water and a salt (and sometimes carbon dioxide).
Acid/Base reactions:
Produce water and a salt (and sometimes carbon dioxide).
Hint: concentrate on the water first. Remember, water has the formula HOH.
Complete and balance the following:
HCl + KOH 
HOH KCl
HCl Ca(OH)2  2
2HOH CaCl2
Require equal numbers

4. Ba(OH) H3PO4 
HC2H3O NaOH 
H2SO KOH 
H2CO NaOH 
NH4OH H2SO4 
NH HCl 

5. Na2CO3 + 2HCl  H2O + CO2(g) + 2NaCl
Conjugate acids and Conjugate bases
HCl + KOH 
HOH KCl
acid
base
conj. acid
conj. base
Na2CO HCl  H2CO NaCl
base
acid
conj. acid
conj. base
Na2CO HCl  H2O + CO2(g) + 2NaCl
acid
base
conj. acid
conj. base

6. NH HCl  NH Cl-

8. What is a strong Acid? Strong Acids:
An Acid that is 100% ionized in water.
Strong Acids:
100% ionized (completely dissociated) in water.
HCl + H2O  H3O+ + Cl-
often written as:
HCl  H+ + Cl-

9. 100% ionized (completely dissociated) in water. HCl + H2O  H3O+ + Cl-
Strong Acids:
100% ionized (completely dissociated) in water.
HCl + H2O  H3O+ + Cl-
Strong Acids:
Perchloric HClO4
Chloric, HClO3
Hydrobromic, HBr
Hydrochloric, HCl
Hydroiodic, HI
Nitric, HNO3
Sulfuric, H2SO4

10. What is a strong Base? NaOH(s)  Na+ + OH-
A base that is completely dissociated in water (highly soluble).
NaOH(s)  Na+ + OH-
Strong Bases:
Group 1A metal hydroxides
(LiOH, NaOH, KOH,
RbOH, CsOH)
Heavy Group 2A metal hydroxides
[Ca(OH)2, Sr(OH)2, and
Ba(OH)2]

11. Strong Acids:
100% ionized (completely dissociated) in water.
HCl + H2O  H3O+ + Cl-
Note the “one way arrow”.
Weak Acids:
Only a small % (dissociated) in water.
HC2H3O2 + H2O  H3O+ + C2H3O2-
Note the “2-way” arrow.
Why are they different?

12. Strong Acids:
HCl HCl
HCl
(H2O)
ADD WATER to MOLECULAR ACID

13. Strong Acids:
Cl-
H3O+
(H2O)
Cl-
H3O+
H3O+
Cl-
H3O+
Cl-
H3O+
Cl-
Note: No HCl molecules remain in solution, all have been ionized in water.

14. Weak Acid Ionization:
HC2H3O2
HC2H3O2
(H2O)
HC2H3O2
HC2H3O2 
HC2H3O2
Add water to MOLECULES of WEAK Acid

15.  Weak Acid Ionization: HC2H3O2 HC2H3O2 H30+ C2H3O2- HC2H3O2 (H2O)
Note: At any given time only a small portion of the acid molecules are ionized and since reactions are running in BOTH directions the mixture composition stays the same.