Given the following reaction at equilibrium `N_(2)(g) + 3H_(2)(g)hArr2NH_(3)(g)`. Some inert gas at constant pressure is added to the system. Predict the following facts:

Options

A. (a) more `NH_(3)`is produced
B. (b) Less `NH_(3)` is produced
C. (c) No affect on the equilibrium
D. (d) `K_(p)` of the reaction is decreased

Answer

To solve the problem, we need to analyze the effects of adding an inert gas to the equilibrium of the reaction:

\[ N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g) \]

### Step-by-Step Solution:

1. **Understand the Reaction**:
The reaction involves nitrogen gas (N2) and hydrogen gas (H2) combining to form ammonia (NH3). The balanced equation shows that 1 mole of N2 reacts with 3 moles of H2 to produce 2 moles of NH3.

2. **Identify the Effect of Inert Gas Addition**:
When an inert gas is added to a system at constant pressure, it does not participate in the reaction. However, it increases the total volume of the system, which can affect the equilibrium position.

3. **Determine the Shift in Equilibrium**:
According to Le Chatelier's principle, if the pressure of a system at equilibrium is changed (by adding an inert gas at constant pressure), the equilibrium will shift towards the side with more moles of gas to counteract the change.

- In our reaction:
- Reactants: 1 mole of N2 + 3 moles of H2 = 4 moles of gas
- Products: 2 moles of NH3

Since there are more moles of gas on the reactant side (4 moles) than on the product side (2 moles), the equilibrium will shift to the left (towards the reactants).

4. **Conclude the Effect on Ammonia Production**:
As the equilibrium shifts to the left, the production of ammonia (NH3) will decrease. Therefore, less NH3 will be produced.

5. **Evaluate the Options**:
- More NH3 is produced: **Incorrect**
- Less NH3 is produced: **Correct**
- No effect on the equilibrium: **Incorrect**
- The equilibrium constant is affected: **Incorrect** (only temperature affects the equilibrium constant)

### Final Answer:
The correct conclusion is that **less NH3 will be produced** when an inert gas is added at constant pressure.

---