ACIDS & ALKALIS

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:

LitmusUniversal Indicator

INDICATORS• Click on the test tubes to find out

how LITMUS indicator works

ACID ALKALI

INDICATORS

indicator turns alkalis _______ .

and acids .

indicator tells us how strong or weak an acid or alkali is.

Litmus blue

red

Universal

MAKING INDICATORSWe can use , ,

And flowers to make indicators.

We need to use this equipment:

berries vegetables

pestle

mortar

Measuring cylinders

The pH Scale

1 6 8 147

NeutralStrong acid Strong alkali

Weak acid Weak alkali

NEUTRALISATIONACID + ALKALI NEUTRAL

+

Testing Soil pH

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