Which of the following is  known as slaked lime?

Calcium hydroxide

The correct answer is option 3. Calcium hydroxide.

Slaked lime, also known as calcium hydroxide, is a chemical compound represented by the formula Ca(OH)₂. It is produced by the hydration (chemical combination with water) of calcium oxide (quicklime). Here's an explanation:

1. Formation:

Calcium hydroxide is formed when calcium oxide (CaO), commonly known as quicklime, reacts with water (H₂O). The chemical equation for this reaction is:

\[ \text{CaO} + \text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 \]

2. Physical Properties:

Calcium hydroxide is a white, crystalline solid that is sparingly soluble in water. It forms a slightly alkaline solution when dissolved in water.

3. Common Names:

Slaked lime is one of the common names for calcium hydroxide. It is also known by other names, including hydrated lime or lime hydrate.

4. Uses:

Calcium hydroxide has various applications across different industries:

• Construction:  It is used in the preparation of mortar and plaster.
• Agriculture: It is used as a soil amendment to raise the pH of acidic soils.
• Water Treatment:  It is employed in water and wastewater treatment processes to control acidity and remove impurities.
• Chemical Processes: It is used in chemical processes and as a precursor to other chemicals.

5. Alkalinity:

Calcium hydroxide imparts alkalinity to solutions. It is considered a strong base and can react with acids to form salts and water.

6. Slaking Process:

The process of producing slaked lime is often referred to as slaking. It involves adding water to quicklime to create a reaction that produces calcium hydroxide.

In summary, slaked lime (calcium hydroxide) is a versatile compound with applications in construction, agriculture, water treatment, and various chemical processes. It is produced through the hydration of quicklime and plays a crucial role in various industries.