1. Topic 10
Acids, Bases & Salts

2. Topic 10-Acids, Bases and Salts (ABS)
Properties of Acids and Bases
Definitions of Acids and Bases
a. Arrhenius
b. Bronsted-Lowry
c. Lewis
Strength of Acids and Bases
Naming Acids and Bases
Reactions with Acids and Bases
a. Acids with Metals
b. Neutralization
I. Strong acid + strong base
II. Strong acid + weak base
III. Weak acid + strong base
IV. Weak acid + weak base
c. Titration pH
Acid/Base Indicators

3. Properties of Acids & Bases
Donate H+ ion (H3O+ ion) in water
React with most metals to produce H2 gas
Affect colors of indicators
Neutralize bases
Sour taste
Electrolyte
Donate OH- ion in water
Affect colors of indicators
Neutralize acids
Bitter taste
Slippery
Electrolyte

4. Tables K & L list some common acids and bases

5. Definitions of Acids and Bases
There are three different definitions of acids/bases
1. Arrhenius
(1884)
Acids-
Are hydrogen containing compounds that ionize to yield hydrogen (H+) ions (also known as
hydronium ions (H3O+) in aqueous solutions
Bases-
are compounds that ionize to yield hydroxide (OH-)
ions in aqueous solutions
Svante Arrhenius

6. 2. Bronsted-Lowry
(1923)
Acids-
An acid is a hydrogen-ion donor
Bases-
A base is a hydrogen-ion acceptor
NH3(aq) + H2O(l) = NH4+(aq) + OH-(aq) B A A B
Johannes Nicolaus Bronsted
Thomas Martin Lowry

7. 3. Lewis (1923)
Acids-
accept a pair of electrons during a reaction
Bases-
donate a pair of electrons during a reaction
Gilbert N. Lewis

8. There are five strong acids
They are considered strong because they ionize 100%
You must memorize the five strong acids
HCl
HBr HI
HNO3
H2SO4

9. Strong Bases
A strong base must be a metal from Group 1 or Group 2 + OH
Gp. 1-
LiOH, NaOH, KOH, RbOH, CsOH, FrOH
Gp. 2-
Be(OH)2, Mg(OH)2, Ca(OH)2, Sr(OH)2, Ba(OH)2, Ra(OH)2
If the metal is from any other group, it is a weak base
*Be careful…bases MUST be a metal + OH
Don’t be fooled…if there is a nonmetal + OH it is an alcohol
Ex.: C2H5OH
C & H are nonmetals so this is NOT
a base but is an alcohol

10. Naming Acids Binary Acids Made up of H + NM Name starts with hydro
Change the ending of the
NM to ic and add the word acid
Ex: HCl
Hydro + Chloric acid
Hydrochloric acid
Ternary Acids
Made up of H + PAI
Does not start with word
hydro
If PAI ends in ate-change
it to ic and end with acid
If PAI ends in ite-change it
to ous and end with acid
Ex: H2SO4
SO4 = sulfate
So it becomes sulfuric acid

11. Lets try some:
HClO-
Hypochlorous acid
HF-
Hydrofluoric acid
HClO2-
Chlorous acid
H2S-
Hydrosulfuric acid
HClO3-
Chloric acid
HNO2-
Nitrous acid
HClO4-
Perchloric acid
HNO3-
Nitric acid
HC2H3O2-
Acetic acid
HMnO4-
Permanganic acid
H3P-
Hydrophosphoric acid
H3PO4-
Phosphoric acid

12. Reactions with Acids
1. Reaction with most metals to produce hydrogen gas
These are just single replacement reactions
Zn + HCl  H2 + ZnCl2
Mg + H2SO4  H2 + MgSO4
Cu + H2S  no reaction

13. 2. Neutralization
A very specific double replacement reaction
Acid + base  salt + water
HCl + NaOH  NaCl + H2O
H2SO4 + Mg(OH)2  MgSO4 + H2O
HC2H3O2 + Ni(OH)3  Ni(C2H3O2)3 + H2O

14. Hydrolysis of a Salt
Four scenarios
1. Strong acid + strong base  neutral salt + water
2. Strong acid + weak base  acidic salt + water
3. Weak acid + strong base  basic salt + water
Weak acid + weak base  ?
Further tests must be performed to determine the type of salt

15. You must also be able to determine the parent acid and parent
base of a salt to determine what type of salt it is
FeSO4
The metal Fe comes from the base Fe(OH)2-weak base
The nonmetal SO4 comes from the acid  H2SO4-strong acid
Therefore…FeSO4 is an acidic salt
How about CaCl2…
The Ca comes from the base  Ca(OH)2-strong base
The nonmetal Cl comes from the acid  HCl-strong acid
Therefore…CaCl2 is a neutral salt

16. What is a salt?
A salt is the product (other than water) of a neutralization reaction; an ionic substance consisting of a metallic cation (not H+) and nonmetal anion (not OH-)
NaCl
FeSO4

17. 4. Titration
A process of determining the concentration of an unknown
solution by a reaction with a solution of known concentration
The formula is on Table T but we must adjust it slightly
(#H+)(MA)(VA) = (#OH-)(MB)(VB)
One liter of 1 M NaOH will completely neutralize one liter
of what concentration of H2SO4?
(#H+)(MA)(VA) = (#OH)(MB)(VB)
(2)(x)(1) = (1)(1)(1)
X = .5 M

18. HCl titrated against NaOH
1 mole of H+ neutralizes 1 mole of OH-
HCl titrated against Ca(OH)2
1 mole of H+ neutralizes .5 mole of Ca(OH)2

19. If you are just asked concentration, use the Molarity formula
When reading a question, if you see the words “neutralize”, “titrate” or “endpoint”, that is your signal to use the titration formula.
If you are just asked concentration, use the Molarity formula
and if necessary, the moles formula

20. Acidity and Alkalinity of Solutions
When [H+] > [OH-] the solution is acidic (acidity)
When [H+] = [OH-] the solution is neutral
When [H+] < [OH-] the solution is basic (alkalinity)
A scale, called the pH scale, has been developed to express [H+]
as a number from 0 to 14. A pH of 0 is strongly acidic, a pH of
7 is neutral and a pH of 14 is strongly basic.
The pH scale is logarithmic. Each pH change signifies a tenfold
change in the concentration of the hydrogen ion.

21. Because [H+] and [OH-] are directly related, a pH change one unit
represents a tenfold increase or decrease of both the hydrogen
ions and hydroxide ion concentration. As the concentration of the
hydrogen ion increases, the concentration of the hydroxide ion
decreases

22. As pH changes from 4 to 5, [H+] decreases by a factor of 10
and [OH-] increases by a factor of 10
As pH changes from 6 to 3, [H+] increases by a factor of 1000 and [OH-] decreases by a factor of 1000
If the pH of a solution was 8 and the hydroxide concentration
increased a hundredth fold, what is the new pH? 10
If the pH of a solution was 4 and the hydroxide concentration is now 1/10 of the original amount, what is the new pH? 3

23. the [H+] increases 100 fold. What is the new pH of the lake?
If nitric acid is spilled into a lake with an original pH of 5,
the [H+] increases 100 fold. What is the new pH of the lake? 3
pH + pOH = 14
[H+][OH-] = 1 x 10-14
[H+]
[OH-] pH
pOH
Acidic or Basic
1 x 10-3
1 x10-11 3 11
acidic
1 x 10-9
1 x 10-5 9 5
basic
1 x 10-8
1 x 10-6 8 6

24. Acid-Base Indicators
An indicator is a substance that changes its color when it gains
or loses a proton
Each indicator has a unique color change that occurs over a
specific pH range
See Table M

25. A solution was yellow in bromthymol blue and blue in bromcresol
green. According to Table M, what could be the pH of the solution?
Between 5.4 and 6.0
A solution was tested with a pH meter and found to have a pH of
7.8. What color would the solution have if the following indicators
were added?
Bromthymol blue-
b. Thymol blue-
blue
yellow