Write the chemical formula of bleaching powder.

Bleaching powder is a chemical compound used primarily as a disinfectant and a bleaching agent. Its chemical formula is \( \text{Ca(OCl)}_2 \), which stands for calcium oxychloride.

Here's a brief explanation of how this formula is derived:

1. **Calcium Oxide**: The compound starts with calcium oxide (\( \text{CaO} \)).

2. **Chlorination**: Calcium oxide reacts with chlorine (\( \text{Cl}_2 \)) to form calcium oxychloride. The reaction can be simplified as:
\[
\text{CaO} + \text{Cl}_2 \rightarrow \text{Ca(OCl)}_2
\]
In this reaction, calcium oxide reacts with chlorine gas to form bleaching powder, which consists of calcium, oxygen, and chlorine.

Bleaching powder is commonly used in water treatment and cleaning processes due to its strong bleaching and disinfecting properties.