When one faraday of electric current is passed, the mass deposited is equal to :

Options

A. one gram equivalent
B. one gram mole
C. electrochemical equivalent
D. half gram equivalent

Answer

To determine the mass deposited when one Faraday of electric current is passed, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Faraday's Law**:
Faraday's first law of electrolysis states that the mass (m) of a substance deposited at an electrode during electrolysis is directly proportional to the quantity of electricity (Q) passed through the electrolyte. The relationship can be expressed as:
\[ m = \frac{Q}{F} \times E \]
where:
- \( m \) = mass of the substance deposited
- \( Q \) = total electric charge (in coulombs)
- \( F \) = Faraday's constant (approximately 96500 C/mol)
- \( E \) = electrochemical equivalent (mass deposited per unit charge)

2. **Charge Calculation**:
One Faraday of electric current corresponds to a charge of approximately 96500 coulombs. Therefore, when we say "1 Faraday," we mean \( Q = 96500 \, \text{C} \).

3. **Electrochemical Equivalent**:
The electrochemical equivalent (E) is defined as the mass of the substance deposited by passing one coulomb of electricity. It can be calculated as:
\[ E = \frac{M}{nF} \]
where:
- \( M \) = molar mass of the substance
- \( n \) = number of electrons transferred per mole of substance (valency or n-factor)

4. **Mass Calculation**:
From Faraday's law, if we pass 1 Faraday of charge, the mass deposited can be expressed as:
\[ m = \frac{96500}{F} \times E \]
Since \( E \) is defined as the mass deposited per coulomb, we can simplify this to find the mass deposited for 1 Faraday of charge:
\[ m = E \times n \]
where \( n \) is the number of moles of electrons transferred.

5. **Conclusion**:
When 1 Faraday of electric current is passed, the mass deposited is equal to 1 gram equivalent of the substance. This is because 1 Faraday corresponds to the charge required to deposit 1 equivalent weight of a substance.

### Final Answer:
The mass deposited when one Faraday of electric current is passed is equal to **1 gram equivalent**.