Question

We come across a number of phenomena in everyday life where the materials are in equilibrium with the surroundings or the reactants are in equilibrium with the products. If the amount of any of the reactants or products is disturbed, the equilibrium shifts to one side or the other. This shifting of equilibrium may be useful or harmful depending upon what type of equilibrium we are dealing with. 

Now answer the following questions: 

(i). Why our clothes dry more quickly when there is a breeze or we shake the clothes as done by a dyer? 

(ii). We sweat more on a humid day but it evaporates when we sit under fan. Why?

Answer 1

(i) This is because water vapors of nearby air are removed and cloth loses more water vapor to re-establish equilibrium with air. 

(ii) More sweating takes place because the surrounding air has large amount of water vapor and our skin cannot lose more to it. The fan removes the humid air and evaporation starts from the skin.