1. Strength of Acids and Bases

2. Ionization
When you put an acid or a base into water, it will break apart into its individual parts.
This is called ionization.
When a compound breaks apart, we can say it is ionized.
Draw the ionization of water below.

3. Strength of Acids and bases
The strength of an acid or base is classified by the degree to which they ionize in water.
A strong acid dissociates in water according to the following generic equation:
HA  H+ (aq) + A- (aq)
Strong acids will dissociate completely if there is enough water.
Because strong acids are ions in water, they will be good conductors of electricity!
Draw what a strong acid would look like in a beaker below.

4. Hydrochloric Acid – HCl
Strong Acids
Hydrochloric Acid – HCl
Hydrobromic Acid – HBr
Hydroiodic acid - HI
Nitric acid – HNO3
Sulfuric acid – H2SO 4
Perchloric acid – HClO4
Periodic acid – HIO4

5. Strength of Acids and Bases
A strong base dissociates in water according to the following generic equation:
MOH  M+ (aq) + OH- (aq)
Strong bases will dissociate completely if there is enough water.
Because strong bases are ions in water, they will also be good conductors of electricity!
Draw what a strong base would look like in a beaker below.

6. Sodium Hydroxide – NaOH Potassium hydroxide – KOH
Strong Bases
Sodium Hydroxide – NaOH
Potassium hydroxide – KOH
Calcium hydroxide – Ca(OH)2
Barium hydroxide – Ba(OH)2
Sodium phosphate – Na3PO4

7. Strength of Acids and Bases
Weak acids and bases do not completely dissociate in water.
Because they are not completely broken down into their individual ions, they will not be good conductors of electricity in water.
Draw what a weak acid would look like in a beaker below.
Draw what a weak base would look like in a beaker below.

8. Strong Acid
Weak Acid

9. Strength and the PH Scale
The farther away from neutral you get, the stronger the acid or base.
Therefore, an acid with a pH of 1 is 10X stronger than an acid with a ph of 2.
Likewise, a base with a ph of 14 is 10,000x stronger than a base with a pH of 10.

10. Strong vs. Weak Strong HCl H+ + Cl-
Whether an acid (or a base) is strong or weak depends on degree of dissociation:
Strong
HCl H+ + Cl-

11. Strong vs. Weak Weak HC2H3O2 H+ + C2H3O2-
Whether an acid (or a base) is strong or weak depends on degree of dissociation:
Weak
HC2H3O H+ + C2H3O2-

12. Strong vs. Weak Strong NaOH Na+ + OH-
Whether an acid (or a base) is strong or weak depends on degree of dissociation:
Strong
NaOH Na OH-
Conc.

13. (Conducts electrical current)
Strong vs. Weak
Greater dissociation = More Ions in Solution!
Electrolyte
(Conducts electrical current)

14. Check Your Understanding
If the following substances had the same concentration (0.01 M), which one would have the lowest pH? HCl or HC2H3O2
Which of the following substances would have the highest conductivity? M or M HCl
3. If the following substances had the same concentration, put them in order of INCREASING pH values:
NH HCl NaOH HC2H3O2

15. Strong vs. Weak
Strong
Weak