In which of the following equilibrium reactions, the equilibrium reactions, the equilibrium would shift to the right, if total pressure is increased

Options

A. `N_(2)(g)+3H_(2)(g) hArr 2NH_(3)(g)`
B. `H_(2)(g)+I_(2)(g) hArr 2HI(g)`
C. `H_(2)(g)+Br_(2)(g)hArr 2HBr(g)`
D. `H_(2)O(g)+CO(g)hArr CO_(2)(g)+H_(2)(g)`

Answer

To determine which equilibrium reaction will shift to the right when the total pressure is increased, we can apply Le Chatelier's principle. This principle states that if a system at equilibrium is subjected to a change in pressure, temperature, or concentration, the system will adjust to counteract that change and restore a new equilibrium.

### Step-by-Step Solution:

1. **Identify the Reactions**: We need to analyze the given equilibrium reactions to see how many moles of gas are present on both sides of the equation.

2. **Apply Le Chatelier's Principle**: According to Le Chatelier's principle, if the pressure is increased, the equilibrium will shift towards the side with fewer moles of gas.

3. **Analyze Each Option**:
- **Option A**: \( N_2 + 3H_2 \rightleftharpoons 2NH_3 \)
- Reactants: \( 1 + 3 = 4 \) moles
- Products: \( 2 \) moles
- Since there are more moles of reactants than products, increasing the pressure will shift the equilibrium to the right (towards the products).

- **Option B**: \( H_2 + I_2 \rightleftharpoons 2HI \)
- Reactants: \( 1 + 1 = 2 \) moles
- Products: \( 2 \) moles
- The number of moles is equal on both sides, so there will be no shift in equilibrium with increased pressure.

- **Option C**: \( H_2 + Br_2 \rightleftharpoons 2HBr \)
- Reactants: \( 1 + 1 = 2 \) moles
- Products: \( 2 \) moles
- Again, the number of moles is equal, so no shift will occur with increased pressure.

- **Option D**: \( H_2O(g) + CO \rightleftharpoons CO_2(g) + H_2 \)
- Reactants: \( 1 + 1 = 2 \) moles
- Products: \( 1 + 1 = 2 \) moles
- The number of moles is equal, so there will be no shift in equilibrium with increased pressure.

4. **Conclusion**: The only reaction that will shift to the right when the total pressure is increased is **Option A**: \( N_2 + 3H_2 \rightleftharpoons 2NH_3 \).

### Final Answer:
The equilibrium will shift to the right in **Option A**: \( N_2 + 3H_2 \rightleftharpoons 2NH_3 \).

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