1. Unit 4
Acids and Bases
Lesson 1
Acid and Base Properties
And Definitions

2. Properties of Bases
Neutralize acids
Are electrolytes that conduct electricity
Change litmus paper blue
Feel slippery
Taste bitter (baking soda)
Ex: NaOH, Ca(OH)2, KOH, Zn(OH)2 -- notice they all contain OH.

3. Properties of Acids Ex: HCl, HNO3, H2SO4 –notice they all contain H.
Neutralize bases
Are electrolytes that conduct electricity
Change litmus paper red
Taste sour (vinegar, lemon juice)
React with metals such as Mg and Zn to make H2
Mg(s)+ 2 HCl (aq)  MgCl2 (aq) + H2(g).
Ex: HCl, HNO3, H2SO4 –notice they all contain H.

4. Notice, a salt does not contain H, or OH.
Salts
A salt is the neutralization product when an acid and a base react to produce water.
HCl + NaOH  NaCl + H2O
Notice, a salt does not contain H, or OH.

5. The Arrhenius Theory of Acids and Bases

6. produces H+ in solution
Arrhenius acid
produces H+ in solution
HCl ®
H Cl-
H+ is called a proton
Arrhenius base
produces OH- in solution
NaOH ® Na OH-

7. Bronsted-Lowry Theory of Acids and Bases

8. Bronsted-Lowry Theory of Acids and Bases
-more general theory
-to accommodate reactions at equilibrium.
-acids as proton donors
-bases as proton acceptors

9. Bronsted Acid
Chemistry 12
A proton donor H+
HCl H2O ®
H3O Cl-
strong
Bronsted Base
Chemistry 12
A proton acceptor
NH H2O ⇄
NH OH- H+
weak

10. Write a Bronsted reaction for the base HCO3-
weak H+ H+
HCO3-
H2O ⇄
H2CO OH-
base
acid
acid
base
HCO3- and H2CO3
H2O and OH-
These are called “Conjugate acid-base pairs”
They differ by one proton H+

11. In Summary 1. Arrhenius bases dissociate in water to produce OH-
2. Bronsted bases accept a proton from water to produce OH-
3. Arrhenius acids dissociate in water to form H+
4. Bronsted acids donate a proton to water to form H3O+
5. H+ is the same as H3O+

12. + H+ is another way to show H3O+. H+ + H2O ⇋ H3O+ Hydronium ion Proton

13. Conjugate acids and bases

14. Conjugates
A conjugate acid-base pair (conjugate pair) is a pair of chemical species which differ by only one proton (H+)
NH4+, NH3
A conjugate acid is the member of conjugate pair that HAS the extra proton.
NH4+
A conjugate base is the member of the conjugate pair that LACKS the extra proton.
NH3

15. Conjugate Acid Conjugate Base One more H+ 1 less H+ C6H5OH C6H5O-
H2CO3
H+ gives a +1 Charge.
HCO3-
H2O
OH-
HPO42-
PO43-
H2PO4-
HPO42-
C6H5COOH
C6H5COO-
NH4+
NH3
Fe(H2O)63+
Fe(H2O)5(OH)2+

16. Acids and Bases Chart 231
Relative Strengths of Bronsted-Lowry Acids and Bases
Aqueous solutions at room temperature.

17. Strong Acids
Weak Acids

18. Strong Acids Left side of Acid Chart -top six-
Completely ionize in water
Are good conductors.
Produce large amounts of H3O+.
Have very large Ka’s, that is why you do not find them on the chart.
Use a “®” and not “⇄” because it is not an equilibrium situation.
HCl + H2O ® H3O Cl-

19. Weak Acids Left side of the Acid Chart below the top six.
Left side of the Acid Chart below the top six.
Do not completely ionize in water.
Are poor conductors.
Produce small amounts of H3O+.
Have small Ka’s, you will find Ka values on the chart.
Use a “⇄” and not “®” It means they are Equilibrium situations!
HF + H2O ⇄ H3O F-
Ka = [H3O+][F-] = 3.5 x from page 334
[HF]
Water is not included because it is a pure liquid! Its concentration is constant!

20. We use H+ and H3O+ interchangeably. They mean the same thing!
You can also write:
 HF + H2O ⇄ H3O F-
HF + H2O ⇌ H F-
[H+][F-]
Ka = = 3.5 x 10-4
[HF]
We use H+ and H3O+ interchangeably. They mean the same thing!

21. Balance these neutralization equations
H2SO4 + NaOH
HCl + Sn(OH)4