Calcium oxide is sparingly soluble in water, and its solubility notably decreases as the water temperature increases.
Calcium oxide, commonly known as quicklime, is a hard, white or grayish-white porous material, typically found as pebbles or powder. It is odorless and undergoes a vigorous exothermic reaction with water, a process known as "slaking," which forms calcium hydroxide.
Key Solubility Values
The solubility of calcium oxide in water is relatively low. This means that only a small amount can dissolve in a given volume of water. An interesting characteristic is its inverse solubility trend with temperature:
- At 25°C: Approximately 1 gram of calcium oxide can dissolve in 840 milliliters of water.
- At 100°C: The solubility significantly decreases, with about 1 gram of calcium oxide requiring 1,740 milliliters of water to dissolve.
This unusual behavior, where solubility decreases with increasing temperature, is less common for solids but is a defining property for calcium oxide in water.
Solubility Overview
To provide a clearer understanding, the solubility data can be summarized as follows:
| Temperature | Approximate Solubility |
|---|---|
| 25°C (Room Temperature) | 1 gram per 840 milliliters |
| 100°C (Boiling Water) | 1 gram per 1,740 milliliters |
Practical Implications
The limited and temperature-dependent solubility of calcium oxide is crucial in various applications:
- Production of Slaked Lime: Calcium oxide reacts with water to form calcium hydroxide (slaked lime), a key component in construction materials like mortar, plaster, and stucco. The controlled addition of water is essential due to the exothermic nature of the reaction.
- Water Treatment: Calcium oxide and its derivatives are used in water treatment for pH adjustment, coagulation, and hardness removal. Its moderate solubility allows for controlled dosing in these processes.
- Industrial Processes: In industries such as steelmaking, agriculture, and papermaking, the specific solubility properties of quicklime are leveraged for various chemical reactions and material preparations.
Understanding the precise solubility of calcium oxide is vital for its safe handling, storage, and effective utilization across diverse industrial and chemical applications.
