In which of the following reactions, the concentration of product is higher than the concentration of reactant at equilibrium? (K = equilibrium constant)

Options

A. `A rarr B`, K = 0.001
B. `M rarr N`,K = 10
C. `X rarr Y`, K = 0.005
D. `R rarr P`, K = 0.01

Explanation

To determine in which of the given reactions the concentration of products is higher than the concentration of reactants at equilibrium, we need to analyze the equilibrium constant (K) for each reaction. The equilibrium constant is defined as follows:

\[ K = \frac{[\text{Products}]^{\text{coefficients}}}{[\text{Reactants}]^{\text{coefficients}}} \]

Where:
- \([\text{Products}]\) is the concentration of the products at equilibrium.
- \([\text{Reactants}]\) is the concentration of the reactants at equilibrium.
- The coefficients are the stoichiometric coefficients from the balanced chemical equation.

### Step-by-Step Solution:

1. **Understand the Relationship Between K and Concentrations:**
- If \( K > 1 \), it indicates that at equilibrium, the concentration of products is greater than that of reactants.
- If \( K < 1 \), it indicates that at equilibrium, the concentration of reactants is greater than that of products.

2. **Evaluate Each Given Reaction:**
- We need to check the value of \( K \) for each reaction provided in the options.

3. **Analyze the Options:**
- **Option 1:** \( K = 0.001 \) (less than 1) - Concentration of reactants > Concentration of products.
- **Option 2:** \( K = 10 \) (greater than 1) - Concentration of products > Concentration of reactants.
- **Option 3:** \( K = 0.05 \) (less than 1) - Concentration of reactants > Concentration of products.
- **Option 4:** \( K = 0.01 \) (less than 1) - Concentration of reactants > Concentration of products.

4. **Identify the Correct Option:**
- From the analysis, only **Option 2** with \( K = 10 \) indicates that the concentration of products is higher than the concentration of reactants at equilibrium.

### Conclusion:
The reaction in which the concentration of products is higher than the concentration of reactants at equilibrium is the one with \( K = 10 \).

### Final Answer:
**Option 2 (K = 10)**