CHEMISTRY [2 Mark Question Answer]

Conservation of water is the means of preventing wastage of water so that clean water can be obtained by preventing pollution of water and by protecting the sources of water. Polluted water acts as a carrier for germs which causes various diseases.

Rainwater harvesting which is a means of utilizing rainwater instead of allowing it to be wasted to be conducted by building tanks or pits in low lying areas and collecting rooftop rainwater through pipes into tanks.

The ways in which we can conserve water are as follows:
1. Use a bucket for taking it.
2. Make sure, water does not overflow from overhead tanks of your house.
3. Close the tap when you are brushing your teeth.
4. Wash fruits, vegetables in a bowl of water, rather than under a running tap. Water used for washing vegetables may be used to water plants in the garden.

Three main causes of water pollution :
1. Addition of waste products from homes.
2. Addition of waste products from agriculture.
3. Addition of waste from industries.
4. Addition of sewage in water bodies.

When it rains heavily water runs into streets, drains, and wasted. we can not make use of it. Our purpose is to catch this rainwater, store it for future use when we actually need it. For this harvesting of rainwater should be done. Rainwater is collected from the roofs and verandas of the buildings with the help of pipes and carried to tanks for storage and is used at the time of need when it is not raining.

Sometimes we see water droplets on the outer surface of the glass containing ice-cold water, this is because the water vapour presents in the air, on coming in contact with the cold glass of water, loses energy and gets converted into the liquid state, which we see as water droplets.

Water cycle: The change of water from one form to another in nature which results in a continuous circulation of water from earth’s surface to the atmosphere and from the atmosphere back to the earth’s surface is called water cycle.
Importance of water cycle:
1. It assures a continuous supply of water to us.
2. In controlling the climatic conditions all over the world.

Springwater is free from suspended impurities and germs (harmful bacteria)as water has been filtered through different layers of soil and is fit for drinking. Springwater contains dissolved impurities which are due to the nature of soil surrounding the spring and cannot be used for laboratory purposes, where distilled water free from impurities is needed

Water is a polar covalent compound. When it comes in contact with any substance it breaks the electrostatic forces holding the molecules of that substance. Thus, the molecules break loose from the substance and hence dissolve in water. Thus, water is called a universal solvent and an alkali is not.

The Occurrence of water in three different states are:
1. Solid-state: As snow and frost.
2. Liquid state: In seawater, river water, and lake water.
3. Gaseous state: As water vapour in the air the amount depending on climatic conditions.

Uses of Water in Industry:
1. Water generates electricity in hydroelectric power stations.
2. Water generates steam in boilers, used for various industrial purposes.
3. Water finds application in chemical & other industries for cooling & cleaning operations.

Sources of Water below the earth’s surface are:

1. Wellwater: Above the impervious rocky layers, the earth’s surface is well water which contains soluble impurities.
2. Springwater: Natural water accumulated above the rocky layers of the earth which forcefully comes out under pressure from the earth’s surface is spring water & contains soluble salts & minerals.

The following Substances will form a solution in the same.
(a) sodium carbonate
(d) sodium sulphate
(e) table salt
(j) honey