1. ACIDS & ALKALIS

2. Acids & Alkalis Acids and alkalis are chemical opposites
We can test whether a substance is acid or alkali by using an indicator. There are different indicators including:
Litmus
Universal Indicator

3. INDICATORS
Click on the test tubes to find out how LITMUS indicator works
ACID
ALKALI

4. INDICATORS blue indicator turns alkalis _______ . and acids .
indicator tells us how strong or weak an acid or alkali is.
Litmus
red
Universal

5. MAKING INDICATORS We can use , , And flowers to make indicators.
We need to use this equipment:
berries
vegetables
Measuring cylinders
pestle
mortar

6. The pH Scale Weak acid Weak alkali Strong acid Strong alkali Neutral 16 8 14 7
Strong acid
Strong alkali
Neutral

7. NEUTRALISATION
ACID + ALKALI NEUTRAL +

8. Testing Soil pH alkaline acidic lime
Soils have different pH’s. If the soil is pH 5
it will be If it is pH 10 it will be
. To make acidic soil neutral we
can add
alkaline
acidic
lime