If the back of your hand is moistened with alcohol, you will find that it rapidly becomes dry ,But if we do so with water it does not get dryer rapidly . Why?
The alcohol on our hand absorbs it's latent heat of vaporisation from the surface of our hands and evaporates.Drawing heat and therefore, cooling our hand in the process.
Alcohol has tendency to evaporate fastly so when it evaporate it takes away the heat present in the hand along with it . So it causes cooling
alocohol is easy toevaporate, however, its sturcture (helping attache itself two water molecules) allows the water there to go with it.
Due to the latent heat of vaporisation and its rapidly because the boiling point of alcohol is less
Because the alcohol on your hands absorbs it latent heat of vapo.
When the back of your hand is moistened with alcohol, it rapidly becomes dry due to the evaporation of alcohol. This is because alcohol has a lower surface tension and a lower boiling point compared to water. Surface tension refers to the cohesive forces between liquid molecules, which determine how tightly the molecules are held together at the liquid-air interface.
Alcohol molecules have weaker cohesive forces, so they evaporate more quickly. As a result, alcohol molecules easily escape the liquid surface and enter the surrounding air, leading to the rapid drying of the hand.
On the other hand, water has relatively stronger cohesive forces, resulting in a higher surface tension. It requires more energy to evaporate water molecules compared to alcohol molecules. Therefore, water evaporates more slowly and does not dry the hand as rapidly as alcohol.
To summarize, the different evaporation rates of alcohol and water are due to their varying surface tensions and boiling points. Alcohol evaporates quickly because of its lower surface tension and boiling point, while water evaporates more slowly due to its higher surface tension.