Question

State Henry’s law and mention some important applications?

Answer 1

We must remember that the solubility of ionic and molecular solids increases with increase in temperature, whereas the solubility of gas decreases with increases in temperature. We know that solubility of gas is inversely proportional to its temperature. Henry law was given by William Henry.

Complete step by step answer:
-We can explain Henry’s law as gas solubility present in the liquid is straightly proportional to the gas partial pressure present above the liquid.
-For ionic/molecular solids, the solubility remains unaffected with respect to pressure.
-For gases, the change in pressure would affect the solubility.
-The solubility of a gas in liquid is directly proportional to its partial pressure at any given temperature. -At pressures of few atmospheres or less, the solubilities of gases obey Henry's law. The expression for Henry’s law is given as,
$C = kP$
Where,
$C$ represents concentration of the gaseous substance in solution
$k$ represents proportionality constant
$P$ represents partial pressure of the gaseous solute in contact with the solution.
-The unit of proportionality constant depends on the units of concentration and the pressure.
-Some of the important applications of Henry’s law are in packing of soda cans and in deep-sea diving.
Soda cans: We pack soda water bottles under higher pressures to raise the solubility of carbon dioxide gas. When soft drinks are opened some of the gas liberates giving a particular pop. This is because of the lower pressure above the liquid and carbon dioxide is liberated out in bubbles.
-Deep-sea diving: Helium is less soluble in nitrogen in our blood. In the deep sea, the surface of the water is less than the pressure. When the divers come faster towards the water surface, the pressure gets reduced and the dissolved nitrogen returns from blood and creates bubbles in veins. So, divers use oxygen diluted with helium.

Note:
Another application of Henry’s law is respiration. In the process of respiration, the amount of oxygen which is dissolved in the bloodstream is proportional to the partial pressure of the oxygen present in the alveoli air. At high altitudes levels, the partial pressure of oxygen is less when compared to partial pressure of oxygen present at ground level. This results in lower concentration of oxygen in tissue climbers and oxygen. Because of this low blood oxygen, climbers turn weak and forgetful as a symptom of a condition called anoxia.