Chapter 16 Acid and Alkali

1. Different substances have different chemical properties.
2. Substances can be classified as having these properties.
a)acidic

b)alkaline

c)neutral

3. A substance can be tested to see if it is acidic, alkaline or neutral using a litmus paper.

Red and Blue litmus paper

The properties of acidic, alkaline and neutral substances

Acidic substances

1. An Acidic substance has a sour taste.

2. It changes blue litmus paper to red.

3. If the acidic substance is tested with a red litmus paper, no colour change will be seen.

4. A strong acid is corrosive and can burn the skin.

5. The acidic substances are such as:

a)Vinegar

b)Grapes

c)Carbonated drinks

d)Pineapple

e)Orange

Alkaline Substances

1. Alkaline substances taste bitter and feel ‘soapy’ to touch.

2. It changes red litmus paper to blue.

3. If the alkaline substance is tested with a blue litmus paper, no colour change will be seen.

4. A strong alkali is corrosive and can burn the skin.

5. The alkaline substances are such as:

a)Baking powder

b) Soap

c)Limewater

Neutral Substances

1. A neutral substance does not have an acidic or alkaline property.

2. It will not change the colour of blue or red litmus paper.

3. If an acidic substance is mixed with an alkaline substance, a neutral substance is formed.

4. The neutral substances are:

a)Sugar

b)Salt

c)Rice

d)Honey

e)Mineral water