Consider the following reaction at equilibrium and determine which of the indicated changes will cause the reaction to proceed to right.
(1) `CO(g)+3H_(2)(g)hArrCH_(4)(g)+H_(2)O(g) (add" "CH_(4))`
(2)`N_(2)(g)+3H_(2)(g)hArr2NH_(3)(g) ("remove" NH_(3))`
(3) `H_(2)(g)+F_(2)(g)hArr2HF(g) (addF_(2))`
(4) `BaO(s)+SO_(3)(g)hArrBASO_(4)(s) (add BaO)`

Options

A. `2,3`
B. 1,4
C. 2,4
D. 2,3,4

Answer

To determine which of the indicated changes will cause the reactions to proceed to the right, we will analyze each reaction based on Le Chatelier's principle. This principle states that if an external change is applied to a system at equilibrium, the system will adjust to counteract that change and restore a new equilibrium.

### Step-by-Step Solution:

1. **Reaction 1:**
\[ \text{CO(g) + 3H}_2\text{(g) } \rightleftharpoons \text{CH}_4\text{(g) + H}_2\text{O(g)} \]
- **Change:** Add CH₄.
- **Analysis:** Adding CH₄ increases the concentration of the product. According to Le Chatelier's principle, the equilibrium will shift to the left to reduce the concentration of CH₄. Therefore, this change will **not** cause the reaction to proceed to the right.

2. **Reaction 2:**
\[ \text{N}_2\text{(g) + 3H}_2\text{(g) } \rightleftharpoons 2\text{NH}_3\text{(g)} \]
- **Change:** Remove NH₃.
- **Analysis:** Removing NH₃ decreases the concentration of the product. To counteract this change, the equilibrium will shift to the right to produce more NH₃. Therefore, this change will cause the reaction to proceed to the right.

3. **Reaction 3:**
\[ \text{H}_2\text{(g) + F}_2\text{(g) } \rightleftharpoons 2\text{HF(g)} \]
- **Change:** Add F₂.
- **Analysis:** Adding F₂ increases the concentration of one of the reactants. According to Le Chatelier's principle, the equilibrium will shift to the right to consume the added F₂ and produce more HF. Therefore, this change will cause the reaction to proceed to the right.

4. **Reaction 4:**
\[ \text{BaO(s) + SO}_3\text{(g) } \rightleftharpoons \text{BaSO}_4\text{(s)} \]
- **Change:** Add BaO.
- **Analysis:** BaO is a solid, and the addition of solids does not affect the equilibrium position. Therefore, this change will **not** cause the reaction to proceed to the right.

### Conclusion:
The changes that will cause the reactions to proceed to the right are:
- **Reaction 2:** Remove NH₃ (correct).
- **Reaction 3:** Add F₂ (correct).

Thus, the correct options are **2 and 3**.