Third trimester

1. Acids and Alkalis

2. Detecting acids and alkalis
- Litmus was used in laboratories around
the world.
- It can be used as a solution of absorbed
into paper strips.

3. Litmus solutionAcid Alkali
Purple + acid red
Purple + alkali blue

4. Litmus paper

5. A R A B
ACID
RED ALKALI
BLUE

6. H.W 111

7. pH scale
- The pH scale starts from 0 – 14.
- The strongest acid is 0 and the strongest alkali is 14.

8. pH Classification
0 - 2 Strong acid
3 - 6 Weak acid
7 Neutral
8 - 11 Weak alkali
12 - 14 Strong alkali
- N.B. An electrical instrument known as pH meter is used to measure pH accurately.
Red – orange – green – blue – purple

10. H.W 101

11. C.W 109

12. C.W 109

13. C.W 109

14. C.W 109