Which of the following metals gives `N_(2)O` gas with dilute `HNO_(3)` ?

Options

A. Zn
B. Cu
C. Au
D. Pb

Explanation

To determine which of the given metals produces N₂O gas when reacted with dilute HNO₃, we will analyze the reactions of each metal with dilute nitric acid.

### Step-by-Step Solution:

1. **Identify the Metals**: The metals we need to consider are Zinc (Zn), Copper (Cu), Gold (Au), and Lead (Pb).

2. **Reaction of Zinc with Dilute HNO₃**:
- The reaction can be written as:
\[ \text{Zn} + 2 \text{HNO}_3 \rightarrow \text{Zn(NO}_3)_2 + \text{H}_2\text{O} + \text{N}_2\text{O} \]
- Balancing the equation gives:
\[ 4 \text{Zn} + 10 \text{HNO}_3 \rightarrow 4 \text{Zn(NO}_3)_2 + 5 \text{H}_2\text{O} + 2 \text{N}_2\text{O} \]
- This indicates that zinc does produce N₂O when reacted with dilute HNO₃.

3. **Reaction of Copper with Dilute HNO₃**:
- The reaction can be written as:
\[ 3 \text{Cu} + 8 \text{HNO}_3 \rightarrow 3 \text{Cu(NO}_3)_2 + 4 \text{H}_2\text{O} + 2 \text{NO} \]
- In this case, copper does not produce N₂O but rather produces NO.

4. **Reaction of Gold with Dilute HNO₃**:
- The reaction can be written as:
\[ \text{Au} + \text{dilute HNO}_3 \rightarrow \text{No Reaction} \]
- Gold does not react with dilute nitric acid, so it does not produce N₂O.

5. **Reaction of Lead with Dilute HNO₃**:
- The reaction can be written as:
\[ 3 \text{Pb} + 8 \text{HNO}_3 \rightarrow 3 \text{Pb(NO}_3)_2 + 2 \text{NO} + 4 \text{H}_2\text{O} \]
- Similar to copper, lead also produces NO and not N₂O.

6. **Conclusion**:
- From the analysis above, only Zinc (Zn) produces N₂O gas when reacted with dilute HNO₃.

### Final Answer:
The metal that gives N₂O gas with dilute HNO₃ is **Zinc (Zn)**.