`(-d[NH_(3])/dt)` represents

Options

A. Rate of formation of Ammonia
B. Rate of decomposition of Ammonia
C. Rate of consumption of `N_(2)`
D. Rate of comsumption of `H_(2)`

Explanation

To understand what `(-d[NH3]/dt)` represents, we can break down the concept step by step.

### Step-by-Step Solution:

1. **Understanding the Expression**:
The expression `(-d[NH3]/dt)` represents the rate of change of concentration of ammonia (NH3) with respect to time (t). The negative sign indicates that the concentration of ammonia is decreasing over time.

2. **Chemical Reaction Context**:
Consider the chemical reaction:
\[ N_2 + 3H_2 \rightarrow 2NH_3 \]
In this reaction, nitrogen (N2) and hydrogen (H2) react to form ammonia (NH3).

3. **Rate of Reaction**:
The rate of a reaction can be expressed in terms of the change in concentration of reactants and products over time. For reactants, the rate is negative because their concentration decreases as the reaction proceeds, while for products, the rate is positive because their concentration increases.

4. **Stoichiometric Coefficients**:
The stoichiometric coefficients from the balanced equation help relate the rates of change of the concentrations of the reactants and products. For NH3, the coefficient is 2, which means:
\[ \text{Rate} = -\frac{1}{2} \frac{d[NH3]}{dt} \]
This indicates that for every 2 moles of NH3 produced, the rate of change of NH3 concentration is halved.

5. **Conclusion**:
Since the expression `(-d[NH3]/dt)` is negative, it indicates the rate of decomposition of ammonia. Therefore, it represents the rate at which ammonia is being consumed in the reaction.

### Final Answer:
`(-d[NH3]/dt)` represents the **rate of decomposition of ammonia**.

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