Assertion (A) Cu cannot liberate hydrogen from acids.
Reason (R ) Because it has positive electrode potential.

Options

A. Both assertion and reason are true, and reason is the correct explanation of the assertion.
B. Both assertion and reason are true but reason is not the correct explanation of assertion.
C. Assertion is not true but reason is true.
D. Both assertion and reason are false.

Explanation

To solve the question regarding the assertion and reason about copper (Cu) and its ability to liberate hydrogen from acids, we can break it down step by step.

### Step 1: Understanding the Assertion
The assertion states that "Cu cannot liberate hydrogen from acids." This means that when copper is placed in an acidic solution, it does not displace hydrogen ions (H⁺) to produce hydrogen gas (H₂).

### Step 2: Understanding the Reason
The reason provided is that "it has a positive electrode potential." Electrode potential is a measure of the tendency of a chemical species to be reduced. A positive electrode potential indicates that the species is less likely to undergo oxidation (lose electrons) compared to hydrogen ions.

### Step 3: Electrochemical Series
In the electrochemical series, metals are arranged based on their standard electrode potentials. Metals with more negative electrode potentials can displace those with more positive potentials from their compounds. Hydrogen has an electrode potential of 0 V.

### Step 4: Position of Copper in the Series
Copper (Cu) has a positive electrode potential, meaning it is positioned below hydrogen in the electrochemical series. This indicates that copper cannot displace hydrogen ions from acids because it is less reactive than hydrogen.

### Step 5: Conclusion
Since copper cannot displace hydrogen ions due to its positive electrode potential, the assertion is true. Furthermore, the reason provided correctly explains why the assertion is true. Therefore, both the assertion and reason are correct, and the reason is the correct explanation for the assertion.

### Final Answer
Both assertion and reason are true, and the reason is the correct explanation for the assertion.

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