1. Introduction to Acids, Bases and pH
Lesson 13

2. Properties of Acids and Bases
Acids are traditionally considered any chemical compound that, when dissolved in water, gives a solution with a hydrogen ion activity greater than in pure water, i.e. a pH less than 7.0. They also:
Taste sour
Are good conductors of electricity (they release H+ ions when they are in water)
React with compounds that contain carbonate
Are generally quite reactive
Turns litmus red

3. When Acids are dissolved in water they release H+ .Ex
HCl(aq)  H+(aq) + Cl-(aq)
Acids are widely used in industry, they are used in many manufacturing processes including; fertilizers, explosives, refining oil, and electroplating materials.

4. Sour milk or tired muscles
Table 1 Examples of common acids include
Common name
Formula
Source or use
Vinegar (acetic acid)
HC2H3O2
Salad dressing
Citric acid
HC6H7O7
Oranges, lemons
Ascorbic acid
HC6H7O6
Vitamin C
Lactic acid
HC­3H5O3
Sour milk or tired muscles
Sulfuric acid
H2SO4
Car batteries

5. Base
A base is most commonly thought of as an aqueous substance that can accept hydrogen ions.
bases can commonly be thought of as any chemical compound that, when dissolved in water, gives a solution with a hydrogen ion activity lower than that of pure water, i.e. a pH higher than 7.0 at standard conditions. They also:

6. Taste bitter
Are good conductors of electricity (They release OH- ions when dissolved in water)
Break down proteins into smaller molecules
May also be called alkaline
Turns litmus blue

7. When bases are released in water they release OH- ions
Example
NaOH (aq)­  Na+ (aq) + OH- (aq)

8. Table 2 Examples of some common bases
Common Name
Formula
Source or use
Sodium hydroxide
NaOH
Drain cleaner
Potassium hydroxide
KOH
Soap, cosmetics
Aluminum hydroxide
Al(OH)­3
Antacids
Ammonium hydroxide
NH­­4OH
Window cleaner.

9. Formulas for Acids and Bases
Common acids can be recognised because their formula begins with (H) hydrogen.
Examples:
H2SO4
H2CO3
H3PO4
HCl

10. Bases
Bases are not as easy to recognise, most will contain a hydroxyl group (OH-).
Ex: NaOH, Mg(OH)2­
Other compounds can form bases when they react with water to form OH- ions. Compounds that contain carbonate (CO32-) or bicarbonate (HCO3-) react

11. The pH Scale
The pH scale is used to represent how acid or basic a solution is. The scale ranges from with very acidic being 0, neutral being 7, and very basic being 14.
Every point on the scale represents a 10 base exponent difference.
Ex lemons (pH = 2.0) are 100 times more acidic than tomatoes (pH = 4.0)
7.0 is neutral (neither acidic nor basic (alkaline)).
Acids range from 0-6.9
Bases range from

12. The pH Scale