The index for the Gold number is:

1. Protective power of lyophilic colloid.

2. Purity of gold.

3. Metallic gold.

4. Electroplated gold.

Milk contains a protein that is very good for health. The protein is:

1. caffeine

2. calciferol

3. keratin

4. casein

When sulphur sol is evaporated solid sulphur is left. On mixing with water no colloidal sol is formed. Sulphur sol is: 

1. hydrophilic

2. hydrophobic

3. reversible

4. lyophilic

Which is not shown by sols?

1. Adsorption

2. Tyndall effect

3. Flocculation

4. Paramagnetism

Lyophobic colloids are:

1. Reversible colloids

2. Irreversible colloids

3. Protective colloids

4. Gum, and proteins