Solubility of Gases in Liquids Quiz

Solubility of Gases in Liquids

• The solubility of gas molecules typically increases with increasing mass of the gas molecules.
• Henry's law states that at constant temperature, the concentration of dissolved gas is proportional to the partial pressure of the gas above the solution at equilibrium.

Pressure Effect

• Gases increase in solubility with an increase in pressure due to more collisions of gas molecules with the solvent surface.
• Increasing pressure results in more solvation and greater solubility.

Temperature Effect

• Gases decrease in solubility with an increase in temperature.
• Increasing temperature leads to an increase in kinetic energy of gas molecules, breaking intermolecular bonds and gas escaping from the solution.
• Example: Carbon dioxide gases escape faster from a carbonated drink as the temperature increases.

Presence of Salts

• Introduction of electrolyte to a solution with dissolved gas results in liberation of gases from the solution, known as "Salting Out".
• This is due to the higher affinity of electrolyte to water molecules, reducing the density of the aqueous environment adjacent to the gas molecules.

Effect of Chemical Reaction

• Henry's law is strictly applicable to gases that do not react with the solvent.
• The reaction between the gas and solvent alters the solubility.
• Example: Carbon dioxide (CO2) is more soluble in water than oxygen (O2), nitrogen (N2), and other gases due to its strong H-bond with water molecules.

Types of Gases and Obeyness of Henry's Law

• Slightly soluble gases (e.g. O2, N2, H2) obey Henry's law.
• Soluble gases (e.g. CO2, Cl2) show considerable deviation from Henry's law.
• Very soluble gases (e.g. Ammonia, NH3) do not obey Henry's law.

Raoult's Law

• Raoult's law is applicable to binary solutions with no energy change, where intermolecular attractive forces between the molecules of the solvent are the same as those between the molecules in the separate components.
• Ideal solutions obey Raoult's law.
• Examples of ideal solutions include benzene + toluene, n-hexane + n-heptane, and ethyl bromide + ethyl iodide.

Real Solutions

• The majority of solutions do not exhibit ideal behavior due to unequal forces of interaction.
• These solutions show either positive or negative deviation from Raoult's law.
• Examples of real solutions with positive deviation include benzene + water, and those with negative deviation include chloroform + acetone, and pyridine + acetic acid.