Question -
Answer -
Henry’s law states thatpartial pressure of a gas in the vapour phase is proportional to the molefraction of the gas in the solution. If p isthe partial pressure of the gas in the vapour phase and x isthe mole fraction of the gas, then Henry’s law can be expressed as:
p = KH x
Where,
KH isHenry’s law constant
Some important applications ofHenry’s law are mentioned below.
(i) Bottlesare sealed under high pressure to increase the solubility of CO2 insoft drinks and soda water.
(ii) Henry’slaw states that the solubility of gases increases with an increase in pressure.Therefore, when a scuba diver dives deep into the sea, the increased seapressure causes the nitrogen present in air to dissolve in his blood in greatamounts. As a result, when he comes back to the surface, the solubility ofnitrogen again decreases and the dissolved gas is released, leading to theformation of nitrogen bubbles in the blood. This results in the blockage ofcapillaries and leads to a medical condition known as ‘bends’ or ‘decompressionsickness’.
Hence, the oxygen tanks used byscuba divers are filled with air and diluted with helium to avoid bends.
(iii) Theconcentration of oxygen is low in the blood and tissues of people living athigh altitudes such as climbers. This is because at high altitudes, partialpressure of oxygen is less than that at ground level. Low-blood oxygen causesclimbers to become weak and disables them from thinking clearly. These aresymptoms of anoxia.