1. Acids and Bases: Theory, pH, and Equilibrium
Ch 17

2. Lewis Theory of A/B
ACID _______an electron pair to form a coordinate covalent bond; a substance with empty or available ________
BASE ________ an electron pair to form a coordinate bond; a substance with an unshared/lone e- pair
Coordinate covalent bond - 1 substance donates 2 electrons to the bond
Lewis Acid or Base?
NH3 H+
Cu2+
H2O
Accept
Donate (bequeath)
Identify the lewis acid and lewis base

3. Arrhenius Acids/Bases
Produce hydrogen ions (H+) in water
Actually….hydronium ions (H3O+)
H+ + H2O --> H3O+
BASES
Produces hydroxide ions (OH-) in water

4. Bronsted-Lowry Acids/Base
ACID - proton (H+) donor
BASE - proton acceptor
Write the reaction of HCl in water acting as a B-L base.
Protons do not exist alone! They always react with water to form hydronium

5. Types of Arrhenius Acids
______protic: lose one proton
HCl, HNO3
______protic: lose up to 2 protons
H2SO4
______protic: lose two or more protons
H3PO4
Mono Di
poly

6. Types of Arrhenius Bases
Accept one proton
NaOH, KOH
Accept 2 proton
SO42-, CO32-
Accept 3 protons
PO43-

7. Amphiprotic Molecules/Ions
Behave as either a B-L acid or base; it just depends ______________
H2O, HPO42-, HCO3-
On what else is around

8. Practice Problems Write the reactions for HPO42- in water
as a B-L acid
as a B-L base.

9. Conjugate Acid-Base Pairs
A pair of compounds (or ions) that differ by one _____(produced in B-L reactions).
Identify the conj. A/B pairs from the reactions of HPO42- in water H+
Label conj acid base from warm ups.

10. Water Autoionization 2 H2O(ℓ) <--> H3O+(aq) + OH–(aq)
Water is in constant equilibrium between H3O+ ions and OH- ions.
Write the equilibrium constant expression for water (Kw)
A proton, H+, never exists alone in an aqueous solution, it is always a hydronium ion, H3O+.
However, chemists will write simply H+ in an aqueous solution as a shorthand.
You may also use this shorthand when presence of the hydronium ion itself is not important. Just don’t forget that when you write H+, it’s really H3O+!

11. Water Autoionization At 25ºC [H3O+] = [OH–] = 1.0×10–7 M, so
Kw = 1.0×10–14
Pure H2O is NEUTRAL, however acids or bases will always maintain this equilibrium
If the [OH-] = 1.2E-4, what is the [H3O+]? Is this substance an acid or base?

12. Water Autoionization ________: increase H3O+ ________: increases OH–
[H3O+] > [OH–]
________: increases OH–
[OH–] > [H3O+]
Acid
base

13. pH/pOH problems _____= -log[H3O+] _____= -log[OH-]
If the [H3O+] = M, what is the pH? pOH?
If the pOH = 4.5, what is the [OH-]? pH?

14. Strong Acids/Bases Complete (100%) ionization Example:
HCl + H2O H3O+ + Cl-
1.0 M ___M ____ M
Ca(OH)2 + H2O Ca2+(aq) + 2OH-(aq)
0.5 M ___ M ___ M

15. Strong Acids/Bases What is the pH of the following strong acids?
0.100 M HNO3
0.024 M H2A (unknown acid)
What is the pH of the following strong bases?
M LiOH
M B(OH)2 (unknown base)

16. pH/pOH Problems
For strong acids or bases, the pH/pOH is directly dependent upon the ________ of the acid.
Acids  pH
Bases  pOH
For weak acids or bases, you must use an ________ to calculate the pH/pOH

17. 7 Strong ACIDS ALL OTHER A CIDS ARE WEAK Hydrochloric acid = _______
Hydrobromic acid = _______
Hydroiodic acid = _______
Nitric acid = _______
Sulfuric acid = _______
Chloric acid = _______
Perchloric acid = _______
HNO3
H2SO4
HClO3,
HClO4
ALL OTHER A CIDS ARE WEAK

18. 8 Strong BASES From solubility rules ALL OTHER BASES ARE WEAK
Group 1 hydroxides
Some Group 2 hydroxides
Ca(OH)2, Sr(OH)2 and Ba(OH)2
ALL OTHER BASES ARE WEAK