A reaction is said to be in equilibrium state when

Options

A. formation of products is minimum
B. reactants are completely converted into products
C. reactants and products are present in equal amounts
D. the rate of forward reaction becomes equal to the rate of backward reaction

Explanation

### Step-by-Step Solution:

1. **Definition of Equilibrium**: A reaction is said to be in an equilibrium state when the rates of the forward and backward reactions are equal. This means that the concentration of reactants and products remains constant over time.

2. **Understanding Forward and Backward Reactions**:
- **Forward Reaction**: In a reversible reaction, the forward reaction is the process where reactants are converted into products. For example, in the reaction A + B ⇌ C, the forward reaction is A + B → C.
- **Backward Reaction**: The backward reaction is the reverse process, where products are converted back into reactants. In the same example, the backward reaction is C → A + B.

3. **Equilibrium Condition**: At equilibrium, the rate at which the reactants are converted into products (forward reaction) is equal to the rate at which the products are converted back into reactants (backward reaction). This does not mean that the concentrations of reactants and products are equal, but rather that their rates of formation and consumption are balanced.

4. **Stability at Equilibrium**: At this point, the system is stable, and there are no net changes in the concentrations of reactants and products, even though both reactions continue to occur. This stability is what defines the equilibrium state.

5. **Final Conclusion**: Therefore, a reaction is in equilibrium when the rate of the forward reaction equals the rate of the backward reaction, leading to constant concentrations of reactants and products.