1. Acids and Bases

2. Some common acids are:
Carbonated drinks carbonic acid
Vinegar acetic acid
Stomach acid hydrochloric acid
Battery acid sulphuric acid
Citrus fruits citric acid

3. Some common bases are:
Drain cleaner sodium hydroxide
Soap/lye sodium hydroxide
Cleaners ammonia

4. Acids, Bases, and Ions
Svante Arrhenius was the first person to explain acids and bases.
An acid produces H, hydrogen ions, when in solution
For example: HCl (aq)  H(aq)+ + Cl(aq)-
A base produces OH, hydroxide ions, when in solution.
For example: NaOH (aq)  Na(aq)+ + OH(aq)-

5. Indicators
It is difficult to tell acids and bases apart, so we use indicators.
Indicators are able to change colour depending upon the solution it is placed in.
Examples:
1. Phenolphthalein is clear
2. Litmus – red litmus and blue litmus.
3. Universal indicator

6. pH Scale
The pH scale was developed to see how concentrated an acid or a base is. Acids and bases can be dilute (very little acid or base in water) or very concentrated (lots of acid or base in water).
The scale runs from 0.0 to 14.0.
Acids are below 7.0
Bases are above 7.0
7.0 is neutral

7. Water is neutral because it has an equal number of hydrogen ions and hydroxide ions.
H2O (aq)  H(aq)+ + OH(aq)-

8. Characteristics of Acids and Bases
Tastes sour
Tastes bitter
Produces H2 gas when reacted with metals
No reaction with metals most of the time
Will conduct electricity
pH below 7.0
pH above 7.0
Turns blue litmus red
Turns red litmus blue
Phenolphthalein will remain clear
Phenolphthalein is magenta/pink