Question

Which of the following substances are used in water purification for a small quantity of water?

• A. Sand
• B. Gravel
• C. Charcoal
• D. Alum

Answer 1

Answer: (A), (B), (C)

The correct options are
A

Sand

B

Gravel

C

Charcoal

One of the ways to purify water is sand gravel experiment. In this experiment gravel and sand are used because they have less water absorption capacity. Charcoal is used because it has more water absorption capacity and cleaning property, so, it absorbs a lot of water and purifies it. Alum is used in water treatment plant during the process called coagulation for the sedimentation of solid waste matter. Water treatment plant purifies a large amount of matter during the same period of time.