Multiple choice

In which of the following conditions will the rate of evaporation arrested to the maximum extent when water in a saucer is left exposed to direct sunlight for two days?

  1. When a pinch of salt is mixed in the water.

  2. When a pinch of sugar is mixed in the water.

  3. When two spoons of oil are added to the water.

  4. When water in the saucer is stirred with a spoon continuously for five to six minutes every hour.

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Evaporation happens faster when there is less exertion or shielding on the surface of the liquid. Oil forms a thin immiscible film on the water surface. Hence, rate of evaporation will be largely arrested. 

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