Electrochemical equivalent of Cu in the reaction
`Cu^(2+) + 2e^(-) rarr Cu(s)` is :

Options

A. `(63.5)/(96.5)`
B. `(63.5)/(96500xx2)`
C. `(63.5xx 2)/(96500)`
D. `(96500)/(63.5xx 2)`

Answer

To find the electrochemical equivalent (Z) of copper (Cu) in the reaction:

\[ \text{Cu}^{2+} + 2e^{-} \rightarrow \text{Cu}(s) \]

we will follow these steps:

### Step 1: Understand the Reaction
In this reaction, copper ions (\( \text{Cu}^{2+} \)) gain 2 electrons to form solid copper (\( \text{Cu}(s) \)). This is a reduction reaction occurring at the cathode.

### Step 2: Determine the Molar Mass of Copper
The molar mass of copper (Cu) is approximately 63.5 g/mol.

### Step 3: Determine the Valency of Copper
In this reaction, copper has a valency of +2 because it is gaining 2 electrons. Thus, the valency (n) is 2.

### Step 4: Calculate the Equivalent Mass
The equivalent mass (E) can be calculated using the formula:

\[ E = \frac{\text{Molar Mass}}{\text{Valency}} = \frac{63.5 \, \text{g/mol}}{2} = 31.75 \, \text{g/equiv} \]

### Step 5: Use Faraday's Constant
Faraday's constant (F) is approximately 96500 coulombs per mole of electrons.

### Step 6: Calculate the Electrochemical Equivalent (Z)
The electrochemical equivalent (Z) is given by the formula:

\[ Z = \frac{\text{Equivalent Mass}}{F} \]

Substituting the values we have:

\[ Z = \frac{31.75 \, \text{g/equiv}}{96500 \, \text{C/mol}} \]

### Step 7: Perform the Calculation
Now, we calculate Z:

\[ Z = \frac{31.75}{96500} \approx 3.29 \times 10^{-4} \, \text{g/C} \]

### Final Answer
The electrochemical equivalent of Cu in the reaction is approximately \( 3.29 \times 10^{-4} \, \text{g/C} \).

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