Oxygen can be obtained from bleaching powder by:

Options

A. adding dilute acid
B. adding alkalies
C. heating with lime
D. heating with a cobalt salt.

Explanation

To obtain oxygen from bleaching powder, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Chemical Composition of Bleaching Powder**:
- Bleaching powder is chemically known as calcium oxychloride and has the formula \( \text{Ca(OCl)}_2 \).

2. **Understand the Reaction Conditions**:
- To release oxygen from bleaching powder, it needs to be heated in the presence of a catalyst. In this case, cobalt(II) chloride (\( \text{CoCl}_2 \)) acts as the catalyst.

3. **Write the Balanced Chemical Equation**:
- The reaction can be represented as follows:
\[ 2 \text{Ca(OCl)}_2 \xrightarrow{\text{heat}, \text{Co}^{2+}} 2 \text{CaCl}_2 + \text{O}_2 \]
- Here, when bleaching powder is heated, it decomposes to form calcium chloride and oxygen gas.

4. **Conclusion**:
- Therefore, oxygen can be obtained from bleaching powder by heating it with cobalt(II) chloride as a catalyst.

### Final Answer:
Oxygen can be obtained from bleaching powder by heating it with cobalt(II) chloride.

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