Assertion: At equilibrium the concentration of all reactants and products are equal.
Reason : At equilibrium , the rate of forward reactions is equal to the rate of backward reactions.

Options

A. If both Assertion and Reason are CORRECT and a Reason is the CORRECT explanations of the Assertion
B. If both Assertion and Reason are CORRECT but Reason is not CORRECT explanation of the Assertion.
C. If Assertion is CORRECT but Reason is INCORRECT.
D. If Assertion is INCORRECT but Reason is CORRECT.

Answer

### Step-by-Step Solution:

1. **Understanding Equilibrium**:
- Equilibrium in a chemical reaction occurs when the rates of the forward and reverse reactions are equal. This means that the concentrations of reactants and products remain constant over time.

2. **Assertion Analysis**:
- The assertion states that "At equilibrium, the concentration of all reactants and products are equal."
- This statement is not universally true. At equilibrium, the concentrations of reactants and products can be different, but they remain constant. Therefore, the assertion is **false**.

3. **Reason Analysis**:
- The reason states that "At equilibrium, the rate of forward reactions is equal to the rate of backward reactions."
- This statement is **true**. At equilibrium, the rate at which reactants are converted to products is equal to the rate at which products are converted back to reactants.

4. **Conclusion**:
- Since the assertion is false and the reason is true, we conclude that the assertion does not correctly explain the reason. Therefore, the correct answer is that the assertion is false, but the reason is true.

### Final Answer:
- The assertion is false, and the reason is true.