Magnesium combines with nitrogen to form a nitride, which reacts with water to form a colourless gas. The gas is

Options

A. `NH_(3)`
B. `N_(2)O`
C. `NO`
D. `N_(2)O`

Explanation

To solve the question regarding the reaction of magnesium with nitrogen and the subsequent reaction with water, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reaction Between Magnesium and Nitrogen**:
- Magnesium (Mg) reacts with nitrogen (N₂) to form magnesium nitride (Mg₃N₂).
- The balanced reaction is:
\[ 3Mg + N_2 \rightarrow Mg_3N_2 \]

2. **Understand the Hydrolysis of Magnesium Nitride**:
- When magnesium nitride reacts with water, it undergoes hydrolysis.
- The reaction can be represented as:
\[ Mg_3N_2 + 6H_2O \rightarrow 3Mg(OH)_2 + 2NH_3 \]
- This reaction produces magnesium hydroxide (Mg(OH)₂) and ammonia (NH₃).

3. **Identify the Colorless Gas Produced**:
- Among the products, ammonia (NH₃) is a colorless gas.
- Ammonia has a characteristic pungent smell, but it is indeed colorless.

4. **Conclusion**:
- Therefore, the colorless gas produced when magnesium nitride reacts with water is ammonia (NH₃).

### Final Answer:
The gas is ammonia (NH₃).

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