1. Unit 11: Acids and Bases
Acids and Bases Models

3. Acids and Bases Acids Bases Tastes sour Turns litmus paper red
Reacts with metal to form H2
Examples: Vinegar, Milk, Soda, Apples, Citrus Fruits
Tastes bitter
Turns litmus paper blue
Feels slippery
Examples: ammonia, lye, drain cleaner, baking soda

4. Acids and Bases
ACIDIC SOLUTION: A solution that contains more hydrogen ions (H+, H3O+) than hydroxide ions.
BASIC SOLUTION: A solution that contains more hydroxide ions (OH-) than hydrogen ions.
WATER: is a neutral solution, meaning it contains the same amount of hydrogen ions as it does hydroxide ions.

5. Acid and Base Models Arrhenius Bronsted-Lowry
Acids PRODUCE hydronium ions
Bases PRODUCE hydroxide ions
Acids are hydrogen DONORS
Bases are hydrogen ion ACCEPTORS

6. Acids and Bases: Arrhenius Model
Acids PRODUCE hydronium ions
HCl  H+ + Cl-
Bases PRODUCE hydroxide ions
NaOH  Na+ + OH-

7. Acids and Bases: Bronsted-Lowry Model
Acids are hydrogen DONORS
Bases are hydrogen ion ACCEPTORS
HCl + H2O  Cl- + H3O+
conjugate conjugate base acid

8. Determining the conjugates:
The conjugate base is the compound from which the hydrogen was removed. It is formed from the acid.
The conjugate acid is the compound to which the hydrogen is added. It is formed from the base.

9. Determining the conjugate acids and bases:
1. H2O + H2O ⇒ H3O+ + OH-
2. H2SO4 + OH- ⇒ HSO4- + H2O
3. HSO4- + H2O ⇒ SO4-2 + H3O+
4. OH- + H3O+ ⇒ H2O + H2O
5. NH3 + H2O ⇒ NH4+ + OH-

10. Acids and Bases: Conjugate Acids and Bases
Identifying Conjugate Acid and Bases

11. Strong Acids and Bases:
Ionize completely in water (good conductors)
Strong Acids:
HCl, HNO3, H2SO4, HBr, HI, HClO4, HClO3
Strong Bases:
LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Ba(OH)2, Sr(OH)2

12. Weak Acids and Bases:
Do not ionize completely in water (poor conductors)
Weak Acids:
HF, HC2H3O2, H3PO4, H2CO3, HCN
Weak Bases:
NH3

13. Acids and Bases Measurement
Acid and Bases are measured on the pH scale
which is derived from the concentration of hydrogen ions present in a solution
Water is neutral because the concentration of hydrogen ions is equal to the concentration of hydroxide ions.
H+ = 1.0 x 10-7 M
OH- = 1.0 x M
H+ = OH-

14. pH Scale:

15. Calculating pH:
pH = -log[H+]
pOH = -log[OH-]
pH + pOH = 14

16. What is the pH and pOH of a 1 x 10-5M HCl solution?
pH = -log(1 x 10-5)
pH = 5
*Remember: pH + pOH = 14
So to calculate pOH: 14 – 5 = 9

17. Practice Problems What is the pH of 0.050M HNO3?

18. What is the pH of 1 x 10-3M NaOH?

19. Determine the pOH of a 735 L of a solution containing 0
Determine the pOH of a 735 L of a solution containing moles of nitric acid.