Solubility
1.Solubility of a Solid in Liquid
a)Nature of Solute and b) Solvent
c)Effect of Temperature
• Exothermic reaction: Releases heat (Δ
H negative)
• Endothermic reaction: Absorbs heat(Δ
H Positive)
Rise in Temperature favours forward
reaction ,solubility increase
Rise in Temperature favours backward
reaction ,solubility decrease
d)Effect of Pressure
• Pressure does not have any significant effect on solubility
of solids in liquids. It is so because solids and liquids are
highly incompressible and practically remain unaffected
by changes in pressure.
2.Solubility of Gas in Liquid
GAS
LIQUID
As the pressure increases, Solubility of
Gas in Liquid increases
Henry’s Law Constant
Different gases have different KH Solubility of gases(O2,N2) increases with
values at the same temperature. decrease of temperature. It is due to this
This suggests that KH is a function reason that aquatic species are more
of the nature of the gas. comfortable in cold waters rather than
in warm waters.
Applications
1. To increase the solubility of CO2 in soft drinks
and soda water, the bottle is sealed under high
pressure.
2. Scuba Diving and Bends: High underwater
pressure increases gas solubility in blood. On
ascending, pressure decreases, releasing nitrogen
as bubbles in the blood, which can block
capillaries and cause bends. Divers use tanks
with a helium-nitrogen-oxygen mix
to prevent this.
3. High Altitude and Anoxia: At high altitudes,
lower pressure reduces oxygen levels in blood,
causing weakness and confusion—a
condition called anoxia.
H2S, a toxic gas with rotten egg like smell, is used for the qualitative
analysis. If the solubility of H2S in water at STP is 0.195 m, calculate
Henry’s law constant.
Henry’s law constant for CO2 in water is 1.67×108 Pa at 298 K.
Calculate the quantity of CO2 in 500 mL of soda water when
packed under 2.5 atm CO2.
