Zinc reacts with excess of caustic soda to form?

Options

A. `Zn(OH)_(2)`
B. `ZnO`
C. `Na_(2)ZnO_(2)`
D. `Zn(OH)_(2).ZnCO_(3)`

Explanation

To determine the product formed when zinc reacts with excess caustic soda (sodium hydroxide), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The reactants in this reaction are zinc (Zn) and caustic soda (sodium hydroxide, NaOH).

2. **Understand the Nature of Zinc**:
- Zinc is an amphoteric metal, meaning it can react with both acids and bases. In this case, it will react with the base (sodium hydroxide).

3. **Write the Reaction**:
- When zinc reacts with sodium hydroxide, it produces sodium zincate and hydrogen gas. The balanced chemical equation for this reaction is:
\[ \text{Zn} + 2\text{NaOH} \rightarrow \text{Na}_2\text{ZnO}_2 + \text{H}_2 \]
- Here, sodium zincate (\(\text{Na}_2\text{ZnO}_2\)) is formed along with hydrogen gas (\(\text{H}_2\)).

4. **Identify the Product**:
- From the balanced equation, we can see that the primary product formed when zinc reacts with excess caustic soda is sodium zincate.

5. **Conclusion**:
- Therefore, the correct answer to the question is that zinc reacts with excess caustic soda to form sodium zincate.

### Final Answer:
Zinc reacts with excess caustic soda to form sodium zincate (\(\text{Na}_2\text{ZnO}_2\)).

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