1. Learning Objectives Acids and Alkalis
To know that solutions can be sorted by whether they are: acid, alkali or neutral.
To understand that an alkali reacts with an acid to cancel it out.
To know that indicators show you how acidic or alkaline a solution is.

2. Acids and alkalis
When a substance dissolves in water it makes a solution.
Solutions can be sorted by whether they are: acid, alkali or neutral.

3. Acids Formed: Characteristics: When the oxide of some non-metals
dissolve in water
they make an acid.
Characteristics:
have a sour taste.
are corrosive to metals.
Excess of H+ ions

4. Acids react with metals

5. Acids Lemon juice vinegar hydrochloric acid
There are many acids present in our everyday lives.
Lemon juice
vinegar
hydrochloric acid
sulphuric acid and nitric acid
citric acid

6. Neutralization
Acids and alkalis react with each other. The alkali cancels out the acid in the reaction.

7. Alkalis feel soapy. are corrosive. Excess of OH- ions
When metals dissolve in water they make an alkali solution.

8. Alkalis
Alkalis are present in many cleaning substances in use in our homes.
Kitchen cleaners
Ammonia
sodium hydroxide, which attack grease.

9. Indicators
Indicators change color in the presence of certain molecules
They change color in acid or alkaline solutions.

10. Litmus Test
Turns red in an acid.
Turns blue in an alkali.

11. Universal Indicator
Universal indicator changes color in acids and alkalis, and measures the strength of the acid or alkali.
ACIDS
ALKALIS
Neutral

12. The pH scale

13. Applications of Neutralization
Insect Stings
Bee stings are acidic
and can be neutralized with
baking soda (bicarbonate of soda).
Wasp stings are alkaline and can be neutralized with vinegar.
Indigestion: Our stomach carries
around hydrochloric acid.
Too much of this leads to indigestion.
To cure indigestion, you can neutralize the excess acid with baking soda or specialized indigestion tablets.

14. More Applications of Neutralization
Factory Waste: Liquid waste from factories is often acidic. If it reaches a river it will destroy and kill sea life of many forms. Neutralizing the waste with slaked lime can prevent this.
Soil Treatment: When soils are too acidic (often as a result of acid rain) they can be treated with slaked lime, chalk or quicklime, all alkalis. Plants and crops grow best in neutral soils.
More Applications of Neutralization