In which of the following does the reaction go almost to completion ?

Options

A. `K_c=10^3`
B. `K_c=10^2`
C. `K_c=10^(-2)`
D. `K_c=10^(-3)`

Answer

To determine in which of the given options the reaction goes almost to completion, we need to analyze the equilibrium constants provided in each option. The equilibrium constant (K) indicates the extent to which a reaction proceeds to form products. A higher value of K suggests that the reaction favors the formation of products, meaning it goes closer to completion.

### Step-by-Step Solution:

1. **Understanding Equilibrium Constant**:
- The equilibrium constant (K) for a reaction can be expressed as:
\[ K = \frac{[\text{Products}]}{[\text{Reactants}]} \]
- A larger value of K indicates that at equilibrium, the concentration of products is much greater than that of reactants, suggesting that the reaction goes almost to completion.

2. **Analyzing the Given Options**:
- The options provided are:
- Option 1: \(10^3\)
- Option 2: \(10^2\)
- Option 3: \(10^{-2}\)
- Option 4: \(10^{-3}\)

3. **Comparing the Values**:
- We need to compare the values of K:
- \(10^3\) (which is 1000)
- \(10^2\) (which is 100)
- \(10^{-2}\) (which is 0.01)
- \(10^{-3}\) (which is 0.001)
- Clearly, \(10^3\) is the largest value, followed by \(10^2\). The other two options are significantly smaller.

4. **Conclusion**:
- Since \(10^3\) is the highest value of K, the reaction corresponding to this equilibrium constant will go almost to completion. Therefore, the correct answer is:
- **Option 1: \(10^3\)**