The solubility of a gas in a liquid refers to the concentration of the dissolved gas in the liquid when it reaches equilibrium with the pure gas present above the solution. Examples of gases in liquids include effervescent preparations with dissolved carbon dioxide, ammonia water, and hydrochloride gas. Furthermore, aerosol products are also considered solutions of gases in liquids when they contain nitrogen or carbon dioxide as propellants.
Factors Affecting Solubility of Gas in Liquids
Factors such as pressure, temperature, the presence of salt, chemical reactions, and micellar solubilization influence the solubility of gases in liquids.
Pressure
Solubility in liquids and solids remains virtually unaffected by changes in pressure. However, when considering the solubility of gases in liquids, the pressure of the gas in contact with the liquid becomes crucial. Higher gas pressure results in increased gas dissolution in liquids, as depicted in Fig. For instance, carbon dioxide in a soda bottle is pressurized before sealing. Upon opening the bottle cap, the pressure above the liquid decreases to 1 atm, causing the soda to fizz. This fizzing is the release of carbon dioxide previously dissolved in the soda. Hence, lower pressure correlates with reduced solubility of carbon dioxide.
Henry’s law describes the impact of pressure on the solubility of a gas. It states that in a dilute solution, the mass of gas dissolved in each volume of liquid solvent at a constant temperature is directly proportional to the partial pressure of the gas. This relationship is expressed mathematically as follows:
Sg = KHPg
Where
Sg = the solubility of the gas in mol/L,
KH = the Henry’s law constant unique to each solute-solvent system,
Pg = the partial pressure of the gas in mmHg.
To determine the quantity of undissolved gas above the solution, subtract the vapor pressure of the pure liquid from the total pressure of the solution.
Example
The solubility of a pure gas in water at 20 °C and at 1 atm pressure is 2.5 × 10−3 mol/L. What will be the concentration of the gas at same temperature at 0.8 atm?
Answer: Using Henry’s law, the solubility (Sg) is related to the partial pressure of the gas (Pg) by the equation (Sg = KH . Pg).
Given that the solubility at 1 atm is (2.5 ×10–3) mol/L, we can find the Henry’s law constant (KH):
Now, we can use this (KH) value to find the solubility (Sg) at 0.8 atm:
Therefore, the concentration of the gas at the same temperature at 0.8 atm is 2×10–3 mol/L.
Solubility of liquids in liquids
The solubility of liquids in liquids refers to the ability of one liquid to dissolve in another liquid, forming a homogeneous mixture. This phenomenon is governed by various factors, including the nature of the liquids involved, temperature, and pressure. The solubility of liquids in liquids is crucial in diverse fields such as chemistry, pharmaceuticals, and the food industry. Different liquids exhibit varying degrees of solubility in one another, leading to distinctions between miscible and immiscible liquids. Miscible liquids dissolve completely in each other, forming a single-phase solution, while immiscible liquids do not dissolve and remain as separate layers. The study of liquid-liquid solubility is essential for understanding processes like extraction, distillation, and the formulation of various products in different industries.
Binary solutions refer to mixtures composed of two components, typically two different chemical substances, which form a homogeneous blend at the molecular level. In binary solutions, one substance is the solute, which is dissolved in the solvent. The combination of a solute and a solvent results in the formation of a solution.
Binary solutions
Binary solutions are extensively studied in chemistry, and they play a crucial role in various scientific and industrial applications. The behavior of binary solutions is often characterized by factors such as temperature, pressure, and concentration, which can influence the solubility and phase behavior of the components.
There are two primary types of binary solutions based on the solubility of the components:
1. Miscible Solutions
In miscible binary solutions, the components are completely soluble in each other in all proportions. There is no limit to their mutual solubility, and a single-phase homogeneous solution is formed. An example of miscible liquids is ethanol and water.
2. Immiscible Solutions
In immiscible binary solutions, the components have limited or no solubility in each other. As a result, they form separate phases within the solution. An example of immiscible liquids is oil and water.
The study of binary solutions is essential in fields such as chemistry, chemical engineering, and materials science, providing insights into the interactions between different substances and contributing to the understanding of phase diagrams, solubility curves, and other thermodynamic properties.
