Suggest an experiment to prove that rate of evaporation of liquid depends on its surface area and vapour already present in surrounding air.

Experiment 1:

Take some tea in a cup and a saucer, and place them in an open area (low humidity) to observe it. You will observe that the tea in saucer evaporates faster than the tea in tea cup. This is because the tea in the saucer has a larger exposed surface area than that in the cup, which allows the particles to escape easily, which ultimately results in a faster rate of evaporation. Hence, the rate of evaporation of liquid does depend on the exposed surface area.

Experiment 2:

Now, place the same cup and saucer filled with tea in a different area (high humidity) to observe it. You will observe that although the relative rate of evaporation of the tea from the cup and saucer remains the same, the time taken for evaporation increases by a significant amount. This situation occurs because the air surrounding the cup and the saucer are almost at the point of saturation and thus it doesn’t want to accept the vapours escaping from the vessels through evaporation, which results in the decrease of the rate of evaporation.Hence, we can conclude that vapour present in the surrounding air also affects the rate of evaporation.