Which of the following loses its activity on storing for a long time ?

Options

A. Chlorine
B. Hydrogen Chloride
C. Bleaching powder
D. Sodium hydroxide

Explanation

To determine which compound loses its activity when stored for a long time, we need to analyze the options provided. The key compound in question is bleaching powder.

### Step-by-Step Solution:

1. **Identify the Compound**: The question refers to a compound that loses its activity over time. The compound we are focusing on is bleaching powder, which has the chemical formula Ca(OCl)₂ (Calcium hypochlorite).

2. **Understanding Bleaching Powder**: Bleaching powder is commonly used as a disinfectant and bleaching agent. It is known for its strong oxidizing properties due to the presence of hypochlorite ions.

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