Heat of formation, `Delta H_(f)^(@)` of an explosive compound like `NCl_(3)` is -

Options

A. Positive
B. Nagative
C. Zero
D. Positive or negative

Explanation

To determine the heat of formation (ΔH_f) of the explosive compound NCl₃, we need to analyze its stability and energy characteristics. Here’s a step-by-step solution:

### Step 1: Understanding Heat of Formation
The heat of formation (ΔH_f) is defined as the change in enthalpy when one mole of a compound is formed from its elements in their standard states. For NCl₃, we consider the reaction of nitrogen (N₂) and chlorine (Cl₂) to form NCl₃.

### Step 2: Reaction of Formation
The balanced chemical equation for the formation of NCl₃ is:
\[ \text{N}_2(g) + \frac{3}{2} \text{Cl}_2(g) \rightarrow 2 \text{NCl}_3(g) \]

### Step 3: Stability and Energy Considerations
NCl₃ is known to be an explosive compound. Explosive compounds typically have high internal energy due to their unstable nature. When they decompose or react, they release a significant amount of energy.

### Step 4: Analyzing the Energy Change
Since NCl₃ is unstable and has high energy compared to its reactants (N₂ and Cl₂), the formation of NCl₃ from these elements involves an increase in energy. This indicates that energy is absorbed during the formation process.

### Step 5: Conclusion on Heat of Formation
Because the formation of NCl₃ requires energy input (due to its instability and high energy), the heat of formation (ΔH_f) for NCl₃ is positive. Thus, we conclude that:
\[ \Delta H_f(NCl_3) > 0 \]

### Final Answer
The heat of formation (ΔH_f) of the explosive compound NCl₃ is positive.

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