Assertion : Copper is unable to displace `H_2` form dil. `H_2 SO_4`
Reason : The standard electrode potential for `Cu^(2+)//Cu` system is greater than that of `H^+//1/2 H_2` system.

Options

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

Answer

To solve the question regarding the assertion and reason about copper's ability to displace hydrogen from dilute H₂SO₄, we will analyze both statements step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Copper is unable to displace H₂ from dilute H₂SO₄." This means that when copper is placed in dilute sulfuric acid, it does not produce hydrogen gas.

2. **Understanding the Reason**:
- The reason provided is that "The standard electrode potential for the Cu²⁺/Cu system is greater than that of the H⁺/1/2 H₂ system." This implies that the tendency of copper ions to gain electrons (be reduced) is higher than that of hydrogen ions.

3. **Standard Electrode Potentials**:
- The standard electrode potential (E°) for the Cu²⁺/Cu half-reaction is approximately +0.34 V.
- The standard electrode potential for the H⁺/H₂ half-reaction is defined as 0.0 V.

4. **Comparing Electrode Potentials**:
- Since +0.34 V (for Cu²⁺/Cu) is greater than 0.0 V (for H⁺/H₂), this indicates that copper ions have a stronger tendency to be reduced (gain electrons) than hydrogen ions.

5. **Conclusion from the Comparison**:
- Because copper ions (Cu²⁺) have a greater tendency to accept electrons compared to hydrogen ions (H⁺), copper cannot displace hydrogen from dilute H₂SO₄. In other words, copper does not have the ability to donate electrons to hydrogen ions, preventing the formation of hydrogen gas.

6. **Final Evaluation**:
- Both the assertion and the reason are correct. The reason correctly explains why copper cannot displace hydrogen from dilute sulfuric acid.

### Final Answer:
Both the assertion and reason are correct, and the reason is the correct explanation of the assertion.