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 can follow these steps:

### Step 1: Understand the concept of Electrochemical Equivalent
The electrochemical equivalent of an element is defined as the mass of that element that is deposited or liberated during electrolysis when one coulomb of electric charge passes through the electrolyte.

### Step 2: Identify the equivalent mass of Copper
The equivalent mass of an element can be calculated using the formula:

\[ \text{Equivalent mass} = \frac{\text{Molar mass}}{n} \]

where:
- Molar mass of copper (Cu) = 63.5 g/mol
- \( n \) is the number of electrons transferred in the reaction. In this case, \( n = 2 \) (since 2 electrons are involved in the reduction of Cu²⁺ to Cu).

### Step 3: Calculate the equivalent mass of Copper
Using the values we have:

\[ \text{Equivalent mass of Cu} = \frac{63.5 \, \text{g/mol}}{2} = 31.75 \, \text{g/equiv} \]

### Step 4: Calculate the Electrochemical Equivalent (Z)
The electrochemical equivalent (Z) can be calculated using the formula:

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

where \( F \) is Faraday's constant, approximately \( 96500 \, \text{C/mol} \).

Substituting the values:

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

### Step 5: Simplify the expression
This gives us:

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

### Final Result
Thus, the electrochemical equivalent of copper in the given reaction is:

\[ Z = \frac{63.5}{2 \times 96500} \, \text{g/C} \]