1. 5.1 Acids and Bases
Acids and bases are very common.
Acids and bases can be very dangerous and corrosive!
NEVER try to identify an acid or base by taste or touch!

2. pH Scale The strength of acids and bases is measured on the pH scale
pH below 7 = acidic pH 7 = neutral pH above 7 = basic
Acids Neutral Bases
If the pH of a solution drops from 7 to 6, it’s concentration changes by a factor of 10.
If the pH of a solution drops from 8 to 6, it’s concentration changes by a factor of 102 = 100

4. pH Indicators The pH of acids and bases cannot be determined by sight.
pH indicators are chemicals that change colour depending on the pH of the solution they are placed in.
Litmus paper is the most common indictor.
Two colours of litmus paper: Blue = basic (>7) and Red = acidic (<7).
A universal indicator contains a number of indicators that turn different colors.

5. pH Indicators
A digital pH meter or probe measures an electrical property of the solution and uses this to determine the pH.

6. Acids In food and drink, taste sour. Are caustic (corrodes stuff).
Named from their anions
If you know a compound’s chemical formula, you may be able to identify it as an acid.
Acids often behave like acids only when dissolved in water.
Therefore, acids are often written with subscript (aq) = aqueous = water

7. Acids
The chemical formula of an acid usually starts with Hydrogen (H).
HCl(aq) = hydrochloric acid
HNO3(aq) = nitric acid
Acids with a carbon usually have the C written first.
CH3COOH(aq) = acetic acid

8. How to Name Acids 3 simple rules:
1. If the anions name ends in –ide, the corresponding acid is named “Hydro________ic acid”
For example,
Formula: HCL
Name: Hydrogen chloride
Hydrochloric acid

9. How to Name Acids
2. If the anions name ends in –ate, the corresponding acid is named “________ic acid”
For example,
Formula: HNO3
Name: Hydrogen nitrate
Nitric acid

10. How to Name Acids
3. If the anions name ends in –ite, the corresponding acid is named “________ous acid”
For example,
Formula: H2SO3
Name: Hydrogen sulfite
Sulfurous acid

11. Name them! HI
HNO2
H2CrO4
HNO3
H2S
H2SO4

12. ACIDS pH of 0 to 6.9 Contribute H+ ions into a solution
Turn litmus paper RED
Conduct ELECTRICITY
Produce H+ gas (when added to some metals)

13. Bases
If you know a compound’s chemical formula, you may be able to identify it as a base.
Bases, like acids, often behave like bases only when dissolved in water
Therefore, bases are often written with subscript (aq) = aqueous = water

14. Bases
The chemical formula of a base usually ends with hydroxide (-OH).
Examples of common bases:
NaOH(aq)
Mg(OH)2(aq)
Ca(OH)2(aq)
NH4OH(aq)

15. How to Name Bases Easier than acids The cation (metal) goes first.
Add “hydroxide” to it.
For example:
NaOH
Ca(OH)2
Fe(OH)3

16. BASES pH of 7.1 to 14 Donate [OH]- ions into a solution
The hydroxide [OH-] group is neutralized by a hydrogen ion to make water.
Turns litmus paper BLUE
Conducts ELECTRICITY
Are Slippery
Are also CAUSTIC

17. Production of Ions
Acids and bases can conduct electricity because they release ions in solution.
Acids release hydrogen ions, H+(aq)
Bases release hydroxide ions OH–(aq)

18. The pH of a solution refers to the concentration of ions it has.
Square brackets are used to signify concentration, [H+(aq)], [OH–(aq)]
High [H+(aq)] = low pH, very acidic
High [OH–(aq)] = high pH, very basic

19. H+(aq) + OH–(aq)  H2O(l)
A solution cannot have BOTH high [H+(aq)] and [OH–(aq)]
they cancel each other out and form water.
This process is called neutralization.
H+(aq) + OH–(aq)  H2O(l)

20. neutralization animations
Litmus paper, pH paper, &
neutralization animations