Question

How is the solubility of a solid in liquid altered by :

Pressure

Answer 1

Solubility :

• The maximum amount of solute that can be dissolved in 100 g of a solvent at a particular temperature is called the solubility of the solute in that solvent. For example, 36 g of sodium chloride can be dissolved in 100 g of water at 293 k or 20$°$C . Hence, the solubility of sodium chloride is 36 g.

Pressure :

• Pressure is defined as the force per unit of area on a surface.
• $\mathrm{pressure}=\mathrm{force}/\mathrm{area}$.

Conclusion :

• For solid and liquid solutes, changes in pressure have practically no effect on solubility.
• This is because solids are incompressible and liquids are negligibly compressible.
• Thus there is no effect of pressure on their solution.
• For gaseous solutes, an increase in pressure increases solubility, and a decrease in pressure decreases solubility.
• For example, when the cap on a bottle of fizzy drink is removed, pressure is released and the gaseous solute bubbles come out of a solution.
• This escape of gas from solution is called effervescence.