`Pb_3O_4` is regrded as a compound oxide of `PbO` and `PbO_2`. How many part of ` PbO_2` are present in it ?

Explanation

To determine how many parts of \( \text{PbO}_2 \) are present in \( \text{Pb}_3\text{O}_4 \), we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Composition of \( \text{Pb}_3\text{O}_4 \)**:
- The compound \( \text{Pb}_3\text{O}_4 \) is regarded as a mixture of lead(II) oxide (\( \text{PbO} \)) and lead(IV) oxide (\( \text{PbO}_2 \)).
- We need to find out how many parts of \( \text{PbO}_2 \) are present in this compound.

2. **Establishing the Ratio**:
- It is known that \( \text{Pb}_3\text{O}_4 \) can be represented as a combination of 2 parts of \( \text{PbO} \) and 1 part of \( \text{PbO}_2 \).
- Therefore, we can write:
\[ \text{Pb}_3\text{O}_4 = 2 \, \text{PbO} + 1 \, \text{PbO}_2 \]

3. **Calculating the Total Parts**:
- The total parts in \( \text{Pb}_3\text{O}_4 \) can be calculated as:
\[ \text{Total parts} = 2 \, (\text{from } \text{PbO}) + 1 \, (\text{from } \text{PbO}_2) = 3 \]

4. **Finding the Parts of \( \text{PbO}_2 \)**:
- Since there is 1 part of \( \text{PbO}_2 \) in the total of 3 parts, we can conclude that:
\[ \text{Parts of } \text{PbO}_2 = 1 \]

5. **Conclusion**:
- Therefore, the number of parts of \( \text{PbO}_2 \) present in \( \text{Pb}_3\text{O}_4 \) is **1 part**.

### Final Answer:
The number of parts of \( \text{PbO}_2 \) present in \( \text{Pb}_3\text{O}_4 \) is **1**.