What is an Unsaturated Solution?
A solution is a mixture of dissolved solute and a solvent. Its concentration is determined by the amount of solute dissolved in a given volume or mass of the solvent. A dilute solution has a lower concentration than a concentrated solution. A sodium chloride solution contains about 20g of sodium chloride dissolved in 180g of water.
Solubility of NaCl in water
Solubility is the extent to which a substance can dissolve in a solvent. It is generally measured in grams per 100 mL of water. The solubility of NaCl in water as an unsaturated solution is 36g/100mL.
The rate at which the solute dissolves and then recrystallizes depends on the temperature of the solution. For example, if you add 40g of NaCl to 100mL of water at 25degC, only 36g will dissolve. This means that the excess will precipitate out.
The solubility of NaCl in water is determined using various methods. One method is the can’t-Hoff equation. This equation estimates the solubility of NaCl at any given temperature, and it is independent of the number of other species present in the solution.
If we want to determine the solubility of NaCl in water as a percentage of water, we can use a formula to calculate the mass of NaCl. A liter of water at 20degC can dissolve up to 357g of table salt. This formula can also be used to calculate the solubility of a liquid.
The relationship between temperature and solubility is not simple or predictable. The solubility of solids increases with increasing temperature, while that of gases decreases. This is a significant concern, especially for the survival of aquatic life. Dissolved oxygen is essential for fish to survive, and if it decreases, it can negatively affect the health of aquatic life.
The solubility of NaCl in water as a solution is measured in grams per 100 mL. A finely divided solute will dissolve faster than a large chunk, and stirring will increase its rate. The solubility of NaCl in water is affected by temperature, so measuring the temperature of the water and other substances in the solution is essential.
The solubility of gases in water depends on their polarity. The more polar a gas is, the more soluble it is in water. For example, soda contains dissolved carbon dioxide. If you open a soda can, you can lower the pressure of the carbon dioxide in the solution. This decreases the solubility of carbon dioxide, and some of it rushes out of the soda.
Solubility of KCl in water
In a saturated solution, potassium chloride dissolves into the water with a solubility of 360g/l, then dissociates into K+ and Cl ions when cooled. However, this process violates the second law of thermodynamics. At 30o C, a saturated solution contains 54g of KCl; at 0o C, only 36g of KCl remains in the solution. The remainder, 18g, precipitates out of the solution.
The solubility of KCl in water is determined by comparing the solute’s solubility with the temperature. The solubility of KCl in an unsaturated solution depends on the solute’s temperature and concentration. KCl is soluble in water at 20degC, while it is insoluble at 80degC.