When aluminium is heated in atomosphere of nitrogen it forms :

Options

A. `AlN`
B. `Al_(2)N`
C. `Al_(3)N`
D. `Al_(2)N_(3)`

Explanation

To determine what happens when aluminum is heated in an atmosphere of nitrogen, we can follow these steps:

### Step 1: Identify the Reactants
- The reactant in this scenario is aluminum (Al) and nitrogen (N₂) gas.

### Step 2: Understand the Reaction
- When aluminum is heated in nitrogen, it reacts to form aluminum nitride (AlN). This is an example of a synthesis reaction where two elements combine to form a compound.

### Step 3: Write the Balanced Chemical Equation
- The unbalanced reaction can be written as:
\[ \text{Al} + \text{N}_2 \rightarrow \text{AlN} \]
- To balance the equation, we need to ensure that the number of atoms of each element is the same on both sides. The balanced equation is:
\[ 2 \text{Al} + \text{N}_2 \rightarrow 2 \text{AlN} \]

### Step 4: Understand the Product
- The product formed is aluminum nitride (AlN). It consists of aluminum ions (Al³⁺) and nitride ions (N³⁻), making it an ionic compound.

### Step 5: Hydrolysis of Aluminum Nitride
- If aluminum nitride is subjected to hydrolysis (reaction with water), it produces aluminum hydroxide (Al(OH)₃) and ammonia gas (NH₃):
\[ \text{AlN} + 3 \text{H}_2\text{O} \rightarrow \text{Al(OH)}_3 + \text{NH}_3 \]

### Step 6: Detection of Ammonia
- Ammonia can be detected through various methods, such as:
- Passing it through hydrochloric acid (HCl) to form ammonium chloride (NH₄Cl).
- Using Nessler's reagent, which gives a color change in the presence of ammonia.

### Conclusion
- Therefore, when aluminum is heated in an atmosphere of nitrogen, it forms aluminum nitride (AlN).

### Final Answer
- The correct answer is aluminum nitride (AlN).

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