The positive value of $E^°_{Cu^{2+}/Cu}$ indicates that

A. copper electrode is a stronger reducing agent than SHE.
B. copper electrode is a stronger oxidising agent than SHE.
C. copper can displace $H_2$ from $HCl(aq)$.
D. copper cannot displace $H_2$ from $HCl (aq)$.

Choose the correct answer from the options given below:

B and D only

The correct answer is Option (1) → B and D only.

Let us break down the concepts behind the electrode potential of copper and the given statements

Understanding Electrode Potential:

Electrode potential (E°) is a measure of the tendency of a metal to be reduced (gain electrons) or oxidized (lose electrons) compared to the standard hydrogen electrode (SHE). SHE is assigned a potential of 0.00 V, and it's used as a reference point.

Standard Electrode Potential of Copper \( E^\circ_{\text{Cu}^{2+}/\text{Cu}} = +0.34 \text{ V} \): This positive value means that **copper ions (\( \text{Cu}^{2+} \)) are more likely to gain electrons and get reduced** compared to hydrogen ions (\( \text{H}^+ \)).

The more positive the \( E^\circ \), the better an oxidizing agent the substance is.

The more negative the \( E^\circ \), the better a reducing agent the substance is.

Analysis of Each Statement:

A. Copper electrode is a stronger reducing agent than SHE.

A reducing agent is a substance that donates electrons in a reaction and itself gets oxidized. If copper were a stronger reducing agent than the Standard Hydrogen Electrode (SHE), it would have to lose electrons more easily than hydrogen, meaning its electrode potential would need to be more negative than that of hydrogen.

The statement is false. The \( E^\circ_{\text{Cu}^{2+}/\text{Cu}} = +0.34 \text{ V} \) means copper ions are easily reduced (gain electrons), not oxidized (lose electrons). Since copper has a positive reduction potential, it is a weaker reducing agent than hydrogen (which has an electrode potential of 0 V). Thus, copper is not a stronger reducing agent than SHE.

B. Copper electrode is a stronger oxidizing agent than SHE.

An oxidizing agent accepts electrons (gets reduced) in a reaction. The more positive the standard reduction potential, the stronger the oxidizing agent. Since \( \text{Cu}^{2+} \) has a positive potential (+0.34 V), it has a strong tendency to accept electrons and get reduced to Cu (solid).

The statement is true. The positive value of \( E^\circ \) indicates that copper ions are more easily reduced than hydrogen ions. This makes the \( \text{Cu}^{2+}/\text{Cu} \) pair a stronger oxidizing agent than the \( \text{H}^+/H_2 \) pair of SHE.

C. Copper can displace \( H_2 \) from HCl (aq).

For copper to displace hydrogen from HCl, copper would need to reduce \( \text{H}^+ \) to hydrogen gas, meaning copper must act as a reducing agent and give up electrons. Metals that displace \( H_2 \) from acids typically have negative reduction potentials because they are strong reducing agents.

The statement is false. The positive reduction potential (+0.34 V) of copper indicates that copper is not a strong enough reducing agent to donate electrons to \( \text{H}^+ \). Therefore, copper cannot displace hydrogen gas from HCl.

D. Copper cannot displace \( H_2 \) from HCl (aq).

As mentioned above, copper would need to donate electrons to hydrogen ions (\( \text{H}^+ \)) in order to displace hydrogen gas from HCl. However, since copper has a positive reduction potential, it is not capable of doing so.

The statement is true. Because copper is not a strong reducing agent, it cannot displace hydrogen from HCl. This statement is correct.

Conclusion:

Statement A is incorrect because copper is not a stronger reducing agent than SHE.

Statement B is correct because copper is a stronger oxidizing agent than SHE.

Statement C is incorrect because copper cannot displace hydrogen from HCl.

Statement D is correct because copper cannot displace hydrogen from HCl.

Thus, the correct answer is B and D only.