Water
- Water is the most basic
and vital substance for all living organisms.
-
The impurities, usually present in water are salts of sodium,
calcium magnesium which make water hard.
- Microorganisms are the most dangerous pollutants of water.
They cause various types of diseases.
- Water is used as source of energy to generate electricity
and as a coolant for heavy machinery.
-
Water covers 70% of the earth surface.
-
Total fresh water of the world 2.6%.
- Oceans contain more than 97% of the total
water.
-
Frozen in glaciers water 1.984%.
-
For human use water available 0.014%.
- Water is one of the six nutrients of human life
(other five being proteins, carbohydrates, fates, minerals and vitamins).
-
There are two methods of cleaning of water. 1) Distillation 2) Water Treatment Plant
- Distillation process consists of two basic
processes boiling and condensation.
Percentage of water on earth surface is about…
NTS
PST 24/11/2019
(11:30)
a) 50%
b) 60%
c) 70%
d) 80%
c
Pesticides and fertilizers are the source of……
a) Domestic waste
b) Agriculture waste
c) Industrial waste
d) Acid rain
b
Harmful bacteria are removed from water by passing …………...
a) Oxygen gas
b) Nitrogen gas
c) Chlorine gas
d) CO2
c
Suspended particles from drinking water are removed by………...
a) Table salt
b) Potash alum
c) Charcoal
d) Chlorine
b
Distillation is a technique of………………….
a) Separation
b) Preparation
c) Disinfection
d) Filtration
a
