Calcium hypochlorite is commonly known as:

bleaching powder

The correct answer is option 2. bleaching powder.

Calcium hypochlorite is a chemical compound with the chemical formula Ca(ClO)₂. It is commonly known as bleaching powder.

1. Composition:

Calcium hypochlorite is composed of calcium cations (Ca²⁺) and hypochlorite anions (ClO⁻).

2. Bleaching Agent:

Bleaching powder is widely used as a bleaching agent and disinfectant. It has the ability to release chlorine gas (\(Cl₂\)) when in contact with water, which contributes to its bleaching and disinfecting properties.

3. Disinfection:

Due to its ability to release chlorine, bleaching powder is often used to disinfect water, swimming pools, and various surfaces. It helps in killing bacteria, viruses, and other microorganisms.

4. Laundry and Textile Industry:

In the textile and laundry industry, bleaching powder is employed for the bleaching of fabrics and textiles.

5. Deodorizing and Cleaning:

It is used for deodorizing and cleaning purposes in various applications.

The term "bleaching powder" reflects its primary application as a bleaching agent. It is an important industrial chemical with widespread use in water treatment, textile industry, and as a general disinfectant.