IAS General Studies Prelims Question No. 9

Mosquitoes breed on stagnant water and their larvae keep floating on water. When oil is sprinkled on the stagnant water, it results in the drowning and death of the larvae. Which of the following is the reason behind death of larvae?
[A] Sprinkling of oil in water reduces surface tension of water
[B] Sprinkling of oil in water increase surface tension of water
[C] Sprinkling of oil in water increases viscocity of water
[D] Sprinkling of oil in water cut of oxygen supply to larvae.
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[A] Sprinkling of oil in water reduces surface tension of water
The property of the surface of the liquid to behave like an elastic membrane is called surface tension. The surface of a liquid resist an external force, due to the cohesive nature of its molecules. When oil is Sprinkled in water, it reduces surface tension of water, resulting in the drowning and death of the larvae.

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