1. 14.1 Properties of Acids and Bases
Chapter 14 Acids & Bases
14.1 Properties of Acids and Bases

2. Properties of Acids Aqueous solutions have a sour taste
Some acids react with active metals to release hydrogen:
Zn(s) + H2SO4(aq) → ZnSO4(aq) + H2(g)
Acids react with bases to produce salts and water:
HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
Acids conduct electric current

3. Properties of Acids Acids change the color of acid-base indicators:
Blue litmus turns red
Methyl orange turns red
Have a pH of less than 7
Donate protons, H+
React with carbonates
Neutralize bases

5. Review: Acids Nomenclature
Binary acids - acids that contain two different elements: hydrogen and one of the more-electronegative elements
prefix "hydro-"
Root of element name
"-ic" ending
example: HBr = hydrobromic acid
Oxyacids - compounds of hydrogen, oxygen, and a third element, usually a nonmetal
no prefixes

7. Some Common Industrial Acids
Sulfuric Acid
Highest volume production of any chemical in the U.S.
Used in the production of paper, fertilizers, petroleum refining & car batteries

8. Some Common Industrial Acids
Nitric Acid
Used in the production of rubber, plastics, pharmaceuticals, fertilizers & explosives
Nitric acid is a volatile acid – its reactive components evaporate easily
Stains proteins yellow (including skin!)

9. Some Common Industrial Acids
Hydrochloric Acid
Used in the pickling of steel
Used to purify magnesium from sea water
Used to correct swimming pool pH
Part of gastric juice, it aids in the digestion of protein
Sold commercially as “Muriatic acid”

10. Some Common Industrial Acids
Phosphoric Acid
A flavoring agent in sodas
Used in the manufacture of detergents & fertilizers
Not a common laboratory reagent

11. Some Common Industrial Acids
Acetic Acid
Concentrated “glacial” acetic acid used in the manufacture of plastics
Used in making pharmaceuticals
Acetic acid is the acid present in vinegar

12. Properties of Bases Aqueous solutions of bases have a bitter taste
Bases change the color of acid-base indicators
Turns red litmus blue
Turns phenolphthalein magenta/purple
Dilute aqueous solutions of bases feel slippery
Bases react with acids to produce salts and water
Bases conduct electric current
Are proton, H+, acceptors
Have a pH value of greater than 7
Neutralize acids

13. Arrhenius Acids & Bases
A chemical compound that increases the concentration of hydrogen ions, H+, in aqueous solution
Arrhenius Base
A substance that increases the concentration of hydroxide ions, OH-, in aqueous solution
Swedish Chemist

14. Aqueous Solutions of Acids
Acids are molecular compounds that ionize in solution
HNO3 + H2O → H3O+ + NO3-
H2SO4 + H2O → H3O+ + HSO4-
H2O + HCl → H3O+ + Cl-
Proton Donor
Proton Acceptor

15. Ionization Equations Instead of:
HCl (g) + H2O (l) → H3O+ (aq) + Cl- (aq)
Sometimes we write this:
HA + H2O (l) → H3O+ (aq) + A- (aq)
Or even this:
HCl (aq) → H+ (aq) + Cl- (aq)
Generic formulas
Leave out water

16. Strength of Acids Strong acids completely ionize in solution. (100%)
Weak acids ionize only slightly and are weak electrolytes.(<5%)

17. Strong Acid Dissociation

18. Weak Acid Dissociation

19. Strength vs. Concentration
Strength refers to ionization in solution.
Concentration refers to the amount of solute in solution.
It is possible to have a concentrated solution of a weak acid or base.
It is also possible to have dilute solution of a strong acid or base.

20. Organic Acids
Organic acids all contain the “carboxyl” group, sometimes several of them.
The carboxyl group is a poor proton donor, so ALL organic acids are weak acids.

21. Examples of Organic Acids
Citric acid in citrus fruit
Malic acid in sour apples
Deoxyribonucleic acid, DNA
Amino acids, the building blocks of protein
Lactic acid in sour milk and sore muscles
Butyric acid in rancid butter

22. Aqueous Solutions of Bases
Ionic bases dissociate when placed in water:
NaOH (s) + H2O (l) → Na+ (aq) + OH- (aq)
Basic solutions are referred to as “alkaline”
Molecular bases produce hydroxide ions through a reaction with water:
NH3 (g) + H2O (l) → NH4+ (aq) + OH- (aq)

23. Strength of Bases Strength of ionic bases in related to solubility:
High solubility = strong base
Low solubility = weak base
Molecular bases tend to be weak regardless of solubility

24. Chapter 14 Acids & Bases
14.2 Acid-Base Theories

25. Bronsted-Lowry Acids & Bases
A molecule or ion that is a proton donor
Bronsted-Lowry Base:
A molecule or ion that is a proton acceptor
ex: hydroxide ion is the acceptor portion of the ionic base, not the whole compound itself
Bronsted-Lowry Acid-Base Reaction:
A reaction in which protons are transferred from the acid to the base.

26. Types of Acids Monoprotic Acids: HC2H3O2 HCl Diprotic Acid: H2SO4
Can donate 1 H
Monoprotic Acids: HC2H3O2
HCl
Diprotic Acid: H2SO4
Triprotic Acids: H3C6H5O H3PO4
* Each successive proton is harder to remove!
Can donate 2 Hs
Can donate 3 Hs
Polyprotic Acids

27. Lewis Acids & Bases Lewis Acid:
An atom, ion or molecule that accepts an electron pair to form a covalent bond
Lewis Base:
An atom, ion or molecule that donates an electron pair to form a covalent bond
Lewis Acid-Base Reaction:
The formation of one or more covalent bonds between an electron-pair donor and electron-pair acceptor.
This definition can be applied to phases other than aqueous reactions.

28. Chapter 14 Acids & Bases
14.3 Acid-Base Reactions

29. Conjugate Acids & Bases
Conjugate Base
The species that remains after an acid has given up its proton
H3PO4 (aq) + H2O (l) ↔ H3O+ (aq) + H2PO4- (aq)
The stronger the acid, the weaker its conjugate base
Acid
Conjugate Base

30. Conjugate Acids & Bases
The species that is formed when a base gains a proton
H3PO4 (aq) + H2O (l) ↔ H3O+ (aq) + H2PO4- (aq)
The stronger the base, the weaker its conjugate acid
Base
Conjugate Acid

31. Proton-Transfer Reactions
These reactions favor the production of the weaker acid and the weaker base.

32. Amphoteric Compounds
Any species that can act as either an acid or a base
Ex: Water as a base:
H3PO4 (aq) + H2O (l) ↔ H3O+ (aq) + H2PO4- (aq)
Ex: Water as an acid:
NH3 (g) + H2O (l) ↔ NH4+ (aq) + OH- (aq)

33. Hydroxyl Group in Molecules
The –OH group in a molecule can be acidic or amphoteric
As the number of oxygens that are bonded around the atom with the –OH group increases, so does the acidity of the compound.
Oxygens pull electron density away from the hydrogen, making it appear more positive (and attractive to water and other bases)

34. Bases Neutralize Acids
Milk of Magnesia contains magnesium hydroxide, Mg(OH)2, which neutralizes stomach acid, HCl.
2 HCl + Mg(OH)2
MgCl2 + 2 H2O

35. Acids Neutralize Bases
HCl + NaOH  NaCl + H2O
Neutralization reactions ALWAYS produce a salt and water.

36. Acids React with Carbonates
2HC2H3O2 + Na2CO3
2 NaC2H3O2 + H2O + CO2

37. Neutralization Reactions
The reaction of hydromium and hydroxide ions to form water molecules
Steps:
Dissociation of a base in water
Acid donates a proton to water
Complete ionic equation
Net ionic equation (no spectator ions)

38. Neutralization
HCl + NaOH → NaCl + H2O

39. Products of Neutralization
HCl + NaOH 
NaCl + H2O
H2SO4 + Ca(OH)2 
CaSO H2O
HNO3 + KOH 
KNO3 + H2O
The products of neutralization are always a ______ and _______.
salt
water

40. Acid Rain SO3 (g) + H2O (l) → H2SO4 (aq) Formation of Acid Rain:
SO2, SO3, CO2, NO, NO2
Formation of Acid Rain:
Nonmetallic oxides enter the atmosphere as a result of burning coal, auto exhaust and other forms of air pollution.
Nonmetallic oxides in the air then combine with water to form oxyacids:
SO3 (g) + H2O (l) → H2SO4 (aq)

41. Effects of Acid Rain on Marble (calcium carbonate)
George Washington:
BEFORE
George Washington:
AFTER
CaCO3 (s) + 2H3O+ (aq) → Ca+2 (aq) + CO2 (g) + 3H2O (l)