1. I. Introduction to Acids & Bases

2. Properties ACIDS BASES H+ or H3O+ cations Sour taste
React with metals to form H2 gas
pH < 7
Ex: vinegar, soda, apples, citrus fruits
BASES
OH- anions
Bitter taste
Slippery feel
pH > 7
Ex: ammonia, antacid, baking soda

3. pH indicators
Indicators are dyes that will change color in the presence of an acid or base.
Some indicators only work in a specific range of pH
Examples
Phenolphthalein
Bromothymol blue
Methyl Red

4. pH indicators Some dyes are natural, like radish skin or red cabbage
Litmus paper, pH paper, or pH meters can also be used to determine pH values

5. HCl + H2O  H3O+ + Cl– B. Definitions – +
Arrhenius - In aqueous solution…
Acids form hydronium ions (H3O+)
HCl + H2O  H3O+ + Cl– H Cl O – +
acid

6. B. Definitions NaOH → Na+ + OH- Arrhenius - In aqueous solution…
Bases form hydroxide ions (OH-)
NaOH → Na+ + OH-

7. HCl + H2O  Cl– + H3O+ B. Definitions acid conjugate base base
Brønsted-Lowry
Acids are proton (H+) donors.
Bases are proton (H+) acceptors.
HCl + H2O  Cl– + H3O+
acid
conjugate base
base
conjugate acid

8. H2O + HNO3  H3O+ + NO3– B. Definitions B A CA CB
The conjugate base forms after the acid donates a Hydrogen
The conjugate acid forms after the base accepts a Hydrogen

9. Amphoteric - can be an acid or a base.
B. Definitions
NH3 + H2O  NH4+ + OH- B A CA CB
Amphoteric - can be an acid or a base.

10. Polyprotic - an acid with more than one H+
B. Definitions
Give the conjugate base for each of the following: HF
H3PO4
H3O+
F -
H2PO4-
H2O
Polyprotic - an acid with more than one H+

11. Br - HSO4- CO32- HBr H2SO4 HCO3- B. Definitions
Give the conjugate acid for each of the following:
Br -
HSO4-
CO32-
HBr
H2SO4
HCO3-

12. C. Neutralization Reactions
Acids react with bases to produce a salt and water
NaOH (aq) HCl(aq) → NaCl + H2O
base acid salt water
Ca(OH) HCl → CaCl H2O
base acid salt water

13. C. Neutralization HCl + NaOH  NaCl + HOH Acid + Base  Salt + Water

14. Acids Acids can be recognized because the start with H Examples HCl
H2SO4 HI

15. Acids & Bases
II. pH

16. [ ] = Concentration (Molarity)
A. Ionization of Water
H2O + H2O H3O+ + OH-
Kw = [H3O+][OH-] = 1.0  10-14
[ ] = Concentration (Molarity)

17. A. Ionization of Water
Find the hydroxide ion concentration of 3.0  10-2 M HCl.
[H3O+][OH-] = 1.0  10-14
[3.0  10-2][OH-] = 1.0  10-14
[OH-] = 3.3  M
Acidic or basic?
Acidic

18. pouvoir hydrogène (Fr.)
B. pH Scale 14 7
INCREASING
ACIDITY
INCREASING
BASICITY
NEUTRAL
pH = -log[H3O+]
pouvoir hydrogène (Fr.)
“hydrogen power”

19. pH of Common Substances
B. pH Scale
pH of Common Substances

20. pH = -log[H3O+] pOH = -log[OH-] pH + pOH = 14 [H3O+] = 10(-pH)
B. pH Scale
pH = -log[H3O+]
pOH = -log[OH-]
pH + pOH = 14
[H3O+] = 10(-pH)
[OH -] = 10(-pOH)

21. B. pH Scale What is the pH of 0.050 M HNO3? pH = -log[H3O+]
Acidic or basic?
Acidic

22. Inverse log (–pH) = Molarity
B. pH Scale
What is the molarity of HBr in a solution that has a pOH of 9.6?
pH = -log[H3O+]
4.4 = -log[H3O+]
-4.4 = log[H3O+]
Inverse log (–pH) = Molarity
[H3O+] = 4.0  10-5 M HBr
pH + pOH = 14
pH = 14
pH = 4.4
Acidic