What is the relation between Faraday and electrochemical equivalent?
2 Answers
The relationship between Michael Faraday and electrochemical equivalent is foundational in the field of electrochemistry. Here’s a detailed explanation of both concepts and how they interconnect:
### Michael Faraday: A Brief Overview
Michael Faraday (1791–1867) was a British scientist who made significant contributions to the fields of electromagnetism and electrochemistry. He is best known for discovering electromagnetic induction and formulating the laws of electrolysis, which describe how electric currents interact with substances in solution.
### Electrochemical Equivalent
The electrochemical equivalent (ECE) of a substance is a measure of how much of that substance is deposited or dissolved during electrolysis for a given amount of electric charge (usually expressed in coulombs). It can be defined mathematically as:
\[
E = \frac{m}{Q}
\]
where:
- \( E \) is the electrochemical equivalent (in grams per coulomb),
- \( m \) is the mass of the substance deposited or dissolved (in grams),
- \( Q \) is the total electric charge passed through the solution (in coulombs).
### Faraday’s Laws of Electrolysis
Faraday established two key laws that describe the relationship between electric charge and chemical change during electrolysis:
1. **First Law of Electrolysis**: The mass of a substance deposited or dissolved during electrolysis is directly proportional to the quantity of electricity passed through the electrolyte. Mathematically, this can be expressed as:
\[
m \propto Q
\]
or
\[
m = k \cdot Q
\]
where \( k \) is a constant (the electrochemical equivalent).
2. **Second Law of Electrolysis**: The masses of different substances deposited or dissolved by the same quantity of electricity are proportional to their equivalent weights. This means that the electrochemical equivalent of different substances can be compared based on their equivalent weights.
### Relation Between Faraday and Electrochemical Equivalent
The relationship can be summarized as follows:
- **Foundation of ECE**: Faraday’s work laid the groundwork for defining the electrochemical equivalent. His laws help us understand how much of a substance will react (either being deposited or dissolved) when an electric current is passed through an electrolyte.
- **Calculating Electrochemical Equivalent**: By using Faraday's first law, one can determine the electrochemical equivalent of a substance by measuring the amount of that substance deposited (or dissolved) after passing a known quantity of electric charge through it.
- **Faraday’s Constant**: Faraday also defined a constant, known as Faraday’s constant (\( F \)), which is the amount of electric charge per mole of electrons (approximately \( 96485 \, \text{C/mol} \)). This constant is essential for calculating electrochemical equivalents, as it links the charge to the number of moles of electrons involved in a reaction.
### Example of Calculation
If you want to determine the electrochemical equivalent of silver (Ag), which has a valency of 1, you can use Faraday's first law. Suppose you passed a charge of 1 coulomb through a silver solution and obtained 0.001118 grams of silver. The electrochemical equivalent \( E \) can be calculated as:
\[
E = \frac{m}{Q} = \frac{0.001118 \, \text{g}}{1 \, \text{C}} = 0.001118 \, \text{g/C}
\]
### Conclusion
In summary, Michael Faraday’s work is instrumental in establishing the principles of electrochemistry, including the concept of electrochemical equivalent. His laws of electrolysis provide a clear framework for understanding how electrical energy is converted into chemical energy during electrolysis, allowing us to quantify this process effectively. The electrochemical equivalent serves as a practical tool for predicting how much of a substance will be transformed during electrochemical reactions based on the amount of electricity involved.
### Michael Faraday: A Brief Overview
Michael Faraday (1791–1867) was a British scientist who made significant contributions to the fields of electromagnetism and electrochemistry. He is best known for discovering electromagnetic induction and formulating the laws of electrolysis, which describe how electric currents interact with substances in solution.
### Electrochemical Equivalent
The electrochemical equivalent (ECE) of a substance is a measure of how much of that substance is deposited or dissolved during electrolysis for a given amount of electric charge (usually expressed in coulombs). It can be defined mathematically as:
\[
E = \frac{m}{Q}
\]
where:
- \( E \) is the electrochemical equivalent (in grams per coulomb),
- \( m \) is the mass of the substance deposited or dissolved (in grams),
- \( Q \) is the total electric charge passed through the solution (in coulombs).
### Faraday’s Laws of Electrolysis
Faraday established two key laws that describe the relationship between electric charge and chemical change during electrolysis:
1. **First Law of Electrolysis**: The mass of a substance deposited or dissolved during electrolysis is directly proportional to the quantity of electricity passed through the electrolyte. Mathematically, this can be expressed as:
\[
m \propto Q
\]
or
\[
m = k \cdot Q
\]
where \( k \) is a constant (the electrochemical equivalent).
2. **Second Law of Electrolysis**: The masses of different substances deposited or dissolved by the same quantity of electricity are proportional to their equivalent weights. This means that the electrochemical equivalent of different substances can be compared based on their equivalent weights.
### Relation Between Faraday and Electrochemical Equivalent
The relationship can be summarized as follows:
- **Foundation of ECE**: Faraday’s work laid the groundwork for defining the electrochemical equivalent. His laws help us understand how much of a substance will react (either being deposited or dissolved) when an electric current is passed through an electrolyte.
- **Calculating Electrochemical Equivalent**: By using Faraday's first law, one can determine the electrochemical equivalent of a substance by measuring the amount of that substance deposited (or dissolved) after passing a known quantity of electric charge through it.
- **Faraday’s Constant**: Faraday also defined a constant, known as Faraday’s constant (\( F \)), which is the amount of electric charge per mole of electrons (approximately \( 96485 \, \text{C/mol} \)). This constant is essential for calculating electrochemical equivalents, as it links the charge to the number of moles of electrons involved in a reaction.
### Example of Calculation
If you want to determine the electrochemical equivalent of silver (Ag), which has a valency of 1, you can use Faraday's first law. Suppose you passed a charge of 1 coulomb through a silver solution and obtained 0.001118 grams of silver. The electrochemical equivalent \( E \) can be calculated as:
\[
E = \frac{m}{Q} = \frac{0.001118 \, \text{g}}{1 \, \text{C}} = 0.001118 \, \text{g/C}
\]
### Conclusion
In summary, Michael Faraday’s work is instrumental in establishing the principles of electrochemistry, including the concept of electrochemical equivalent. His laws of electrolysis provide a clear framework for understanding how electrical energy is converted into chemical energy during electrolysis, allowing us to quantify this process effectively. The electrochemical equivalent serves as a practical tool for predicting how much of a substance will be transformed during electrochemical reactions based on the amount of electricity involved.
Faraday's laws of electrolysis and the concept of electrochemical equivalent are closely related in the context of electrochemical reactions.
### Faraday's Laws of Electrolysis
1. **Faraday's First Law of Electrolysis:** The mass of an element or compound deposited or dissolved at an electrode during electrolysis is directly proportional to the amount of electric charge passed through the electrolyte.
2. **Faraday's Second Law of Electrolysis:** The mass of an element deposited or dissolved by a given quantity of electric charge is proportional to the equivalent weight of the substance.
### Electrochemical Equivalent
The **electrochemical equivalent (E)** of a substance is defined as the mass of the substance deposited or dissolved at an electrode when one coulomb of electric charge passes through the electrolyte. It is a measure of the substance's mass per unit charge and is expressed in grams per coulomb (g/C).
### Relation Between Faraday's Laws and Electrochemical Equivalent
The relationship between Faraday's laws and the electrochemical equivalent can be derived as follows:
1. **Faraday’s Constant (F):** This is the amount of charge (in coulombs) required to deposit or dissolve one mole of an element in an electrolytic cell. Its value is approximately 96485 C/mol.
2. **Electrochemical Equivalent Formula:**
\[
E = \frac{M}{nF}
\]
where:
- \(E\) is the electrochemical equivalent in g/C,
- \(M\) is the molar mass of the element in grams per mole,
- \(n\) is the number of electrons transferred per ion (valency),
- \(F\) is Faraday’s constant.
### Practical Example
Consider the electrolysis of water where hydrogen is evolved. For hydrogen:
- Molar mass (\(M\)) = 2.016 g/mol,
- Valency (\(n\)) = 2 (because each hydrogen molecule requires 2 electrons for its formation).
Using the formula, the electrochemical equivalent of hydrogen can be calculated as:
\[
E = \frac{2.016}{2 \times 96485} \approx 0.0000105 \text{ g/C}
\]
Thus, Faraday’s laws provide a basis for calculating the electrochemical equivalent by linking the amount of substance involved in the reaction with the electric charge passed through the system.
### Faraday's Laws of Electrolysis
1. **Faraday's First Law of Electrolysis:** The mass of an element or compound deposited or dissolved at an electrode during electrolysis is directly proportional to the amount of electric charge passed through the electrolyte.
2. **Faraday's Second Law of Electrolysis:** The mass of an element deposited or dissolved by a given quantity of electric charge is proportional to the equivalent weight of the substance.
### Electrochemical Equivalent
The **electrochemical equivalent (E)** of a substance is defined as the mass of the substance deposited or dissolved at an electrode when one coulomb of electric charge passes through the electrolyte. It is a measure of the substance's mass per unit charge and is expressed in grams per coulomb (g/C).
### Relation Between Faraday's Laws and Electrochemical Equivalent
The relationship between Faraday's laws and the electrochemical equivalent can be derived as follows:
1. **Faraday’s Constant (F):** This is the amount of charge (in coulombs) required to deposit or dissolve one mole of an element in an electrolytic cell. Its value is approximately 96485 C/mol.
2. **Electrochemical Equivalent Formula:**
\[
E = \frac{M}{nF}
\]
where:
- \(E\) is the electrochemical equivalent in g/C,
- \(M\) is the molar mass of the element in grams per mole,
- \(n\) is the number of electrons transferred per ion (valency),
- \(F\) is Faraday’s constant.
### Practical Example
Consider the electrolysis of water where hydrogen is evolved. For hydrogen:
- Molar mass (\(M\)) = 2.016 g/mol,
- Valency (\(n\)) = 2 (because each hydrogen molecule requires 2 electrons for its formation).
Using the formula, the electrochemical equivalent of hydrogen can be calculated as:
\[
E = \frac{2.016}{2 \times 96485} \approx 0.0000105 \text{ g/C}
\]
Thus, Faraday’s laws provide a basis for calculating the electrochemical equivalent by linking the amount of substance involved in the reaction with the electric charge passed through the system.