1. Acid and Bases Chapter 24

2. Examples of Everyday Acids and Bases
Lemon Juice
Vinegar
Stomach Acid (HCl)
Rain water
Toothpaste
Window Cleaner
Toilet Bleach
Baking Soda

3. Litmus Paper
Litmus paper can be used to tell if something is an acid, base or neutral.
Acid
Neutral
Base
Red stays red.
Blue turns red.
Blue stays blue.
Red turns blue.

4. The pH Scale
The pH scale is a scale used to measured how acidic or basic something is.
Acids have a pH of less than 7 (1 to 6).
Neutral substances (e.g. water) have a pH of 7.
Bases have a pH of greater than 7 (8 to 14).
Universal indicator paper can be used to find the pH of a substance.

5. Alkaline An alkali is a base which dissolves in water.
Example: toothpaste
We say the substance is alkaline.

6. Acids and Bases – Chapter 28
Acids and Bases in the Lab
STRONG ACIDS
STRONG BASES
Hydrochloric Acid
HCl
Sulfuric Acid
H2SO4
Sodium Hydroxide
NaOH
Calcium Hydroxide
(Limewater)
Ca(OH)2
Calcium Carbonate
CaCO3

7. Neutralisation
Neutralisation occurs when an acid and a base react to make something which is neutral (pH 7)
Examples of neutralisation reactions:
Putting vinegar (acid) on a wasp sting (basic)
Taking antacid tablets (bases) to neutralise excess stomach acid

8. Indicators To show that neutralisation has occurred we
use an indicator.
An indicator is any substance which can show whether something is an acid or a base by changing colour.
Examples of indicators:
Litmus Paper – red in acid, blue in base
Universal indicator paper - changes colour depending on pH
Methyl Orange – turns form orange to pink when neutralisation occurs.

9. Neutralisation Reactions
When acids and bases neutralise each other they make a salt and water.
Reaction:
Acid Base Salt Water
Hydrochloric Sodium Sodium Water
Acid Hydroxide Chloride
HCl NaOH NaCl H2O
Hydrochloric + Calcium Calcium Water + Carbon
Acid Carbonate Chloride Dioxide
2 HCl CaCO3 CaCl H2O CO2

10. Titration Reaction Titrating Hydrochloric Acid Against
A titration involves measuring the exact volume of acid and base needed to react to make a neutral substance.
Titrating Hydrochloric Acid Against
Sodium Hydroxide
Indicator Used:
Methyl Orange
Hydrochloric

11. What you need to know:
Chapter Chapter 28