Correct Answer - Option 3 : both a and b
Concept:
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Impure water is water with some other compounds like chlorine, fluorine, sand, heavy metals, and other chemicals in it.
Explanation:
We can purify the water by both of these methods easily:
By adding alum:
- Alum is added to water to purify it.
- Alum is aluminium sulfate.
- It acts as a coagulant agent in water and attracts all small particles to make a large impurity particle.
- This impurity particle will reside down and after it, all the floating impurities will get filtered.
- So, it is a good method to purify water.
By boiling:
- Boiling of water is the major way to purify water.
- It is a simple method that can kill all the biological contaminants like parasites or microorganisms from the water.
- We have to boil the water at its highest boiling point for some time in this method.
- It is tried and tested method for all peoples from the centuries.
Thus, impure water can be made pure by adding alum or by boiling.
Other common methods of water purification are as follows:
Filtration:
- It is an excellent method of water purification.
- In this method, you have to pass the water through a filter to remove all the dirt and dust particles from the water.
Distillation:
- It is a method of water purification by using a heat source to vaporize water.
- When the water becomes vapour and it separates all the contaminants from the liquid.
