Question

______ should be sprayed on surface of water.​

Answer 1

Answer:

insecticides is the correct answer.

Answer 2

Oil should be sprayed on the surface of the water.

• Oil should be sprayed on the surface of the water because the surface tension of oil is relatively lesser than that of water so when oil is sprayed on the surface of the water then the force of surface tension of water is larger than that of oil resulting in the stretching of the drops of oil on all sides.

• Thus, the oil spreads over the surface of the water and the oil which is spread over the surface of water blocks access to oxygen in the water of tanks and ponds leading to the prevention of the larvae of disease and preventing mosquitoes to breathe and consequently they die.

• Even a small quantity of oil which floats on the surface of the water may smother mosquito larvae and eventually reduce mosquito breeding.

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