Question

Which process is accompanied by a decrease in entropy?(1) boiling of water(2) condensing of water vapor(3) subliming of iodine(4) melting of ice

Answer 1

The correct answer is option 2. Condensing water vapor is accompanied by a decrease in entropy. Entropy is the degree of disorderliness in a system. We know that among all phases the most ordered is solid which means it has the least entropy while the opposite is the gas phase. 

Answer 2

Answer:

2) condensing of water vapor

Explanation:

Entropy is the measure of disorder in a system. Disorder means how "separated" and distanced the molecules, particles, etc. are from each other. Solids and crystals have rigid structures meaning that they have less disorder than gases and liquids that have free structures. Gases and liquids have a higher disorder than solids and crystalline structures. An increase in entropy means that the disorder is increasing; more heat and energy are being added. A decrease in entropy means that the disorder is decreasing and the structure becomes more rigid and ordered; less heat and energy are being added. So the condensing of water vapor means that disorder is decreasing, thus the entropy is decreasing.

I hope this makes sense :)