The exact solubility of potassium chloride (KCl) in water is 253.9 grams per litre at 20 °C (68 °F).
Potassium chloride is a common ionic salt widely used in various applications, from agriculture to medicine. Its solubility, or the maximum amount that can dissolve in a given amount of solvent at a specific temperature, is a crucial property determining its utility.
Understanding Potassium Chloride's Solubility
Solubility indicates how much of a substance (solute) can be dissolved in a solvent to form a saturated solution. For potassium chloride, the provided reference specifies its solubility in water at a standard room temperature:
- Solute: Potassium Chloride (KCl)
- Solvent: Water
- Temperature: 20 °C (68 °F)
- Solubility Value: 253.9 grams per litre
This means that at 20 °C, you can dissolve up to 253.9 grams of potassium chloride in one litre of water before the solution becomes saturated, and any additional KCl would remain undissolved as a precipitate.
Key Properties of Potassium Chloride
Beyond its solubility, other fundamental properties of potassium chloride contribute to its behavior and applications.
| Property | Value | Unit |
|---|---|---|
| Molecular Mass | 74.551 | grams per mole (g/mol) |
| Solubility in Water | 253.9 (at 20 °C / 68 °F) | grams per litre (g/L) |
| Density | 1.984 | grams per millilitre (g/mL) |
These properties are essential for chemists and industries working with potassium chloride, enabling accurate calculations for solution preparation, storage, and transport.
Factors Affecting Solubility
While the provided value is specific to 20 °C, it's important to note that solubility is generally influenced by several factors:
- Temperature: For most solids, including potassium chloride, solubility increases with increasing temperature. This is why solubility data always specifies a temperature.
- Pressure: For solid solutes, pressure has a negligible effect on solubility.
- Nature of Solute and Solvent: The "like dissolves like" principle applies, meaning polar solvents like water effectively dissolve polar or ionic compounds like KCl.
Practical Implications and Applications
The solubility of potassium chloride has significant practical implications:
- Fertilizers: KCl is a primary source of potassium for plants, used extensively as a fertilizer (often referred to as Muriate of Potash). Its solubility allows it to dissolve in soil water, making potassium ions available for plant uptake.
- Food Additive: It's used as a salt substitute and a gelling agent in food products. Its solubility ensures it blends well into food matrices.
- Medical Uses: In medicine, potassium chloride solutions are administered to correct potassium deficiencies (hypokalemia). The precise solubility data is critical for formulating intravenous solutions and oral supplements accurately.
- Industrial Processes: Used in various chemical processes, including the production of potassium hydroxide and chlorine.
Understanding the precise solubility of potassium chloride ensures effective and safe use across these diverse applications, allowing for the accurate preparation of solutions and control over its behavior in different environments.
