What is electrochemical equivalent class 12?
2 Answers
Electrochemical equivalent (ECE) is a concept in electrochemistry that refers to the mass of a substance produced or consumed at an electrode during electrolysis when a specific amount of electric charge passes through the electrolyte. It is an important parameter in understanding the quantitative relationships between electric charge and chemical change.
### Definition and Formula
The electrochemical equivalent of a substance can be defined using Faraday's laws of electrolysis. The first law states that the mass (\(m\)) of a substance deposited or dissolved at an electrode is directly proportional to the quantity of electric charge (\(Q\)) passed through the electrolyte:
\[
m = Z \cdot Q
\]
Where:
- \(m\) = mass of the substance (in grams)
- \(Q\) = electric charge (in coulombs)
- \(Z\) = electrochemical equivalent (in grams per coulomb)
### Units
- The unit of ECE is typically grams per coulomb (g/C), which indicates how many grams of a substance will be deposited or dissolved when one coulomb of electric charge is passed.
### Calculation of Electrochemical Equivalent
To calculate the electrochemical equivalent, you can use the following steps:
1. **Identify the Substance**: Determine the chemical involved in the electrolysis process.
2. **Determine the Valency**: Find the valency (\(n\)) of the substance. For instance, if you are working with copper ions (\(Cu^{2+}\)), the valency is 2.
3. **Molar Mass**: Find the molar mass (\(M\)) of the substance. For copper, \(M = 63.5 \, g/mol\).
4. **Use the Formula**: The electrochemical equivalent can be calculated using the formula:
\[
Z = \frac{M}{n \cdot F}
\]
Where:
- \(M\) = molar mass of the substance (g/mol)
- \(n\) = number of moles of electrons transferred per mole of substance (valency)
- \(F\) = Faraday's constant (\(F \approx 96500 \, C/mol\)), which is the charge of one mole of electrons.
### Example Calculation
Let's calculate the electrochemical equivalent of copper (\(Cu\)):
1. Molar mass of copper, \(M = 63.5 \, g/mol\)
2. Valency of copper, \(n = 2\) (since \(Cu^{2+}\) needs 2 electrons)
3. Using Faraday's constant, \(F = 96500 \, C/mol\)
Now, substituting these values into the formula:
\[
Z = \frac{63.5}{2 \times 96500} \approx 0.000329 \, g/C
\]
This means that approximately 0.000329 grams of copper will be deposited for every coulomb of charge passed.
### Applications
1. **Electroplating**: Understanding ECE helps in controlling the thickness of coatings applied during electroplating.
2. **Battery Technology**: It aids in calculating the amount of materials needed in batteries.
3. **Electrolysis Processes**: ECE is crucial in processes like electrolysis for separating elements or compounds.
### Conclusion
Electrochemical equivalent is a fundamental concept that bridges electrical and chemical phenomena, allowing for the quantitative analysis of reactions occurring during electrolysis. By knowing the electrochemical equivalent of a substance, one can accurately predict the mass of a material that will be produced or consumed in electrochemical processes, which has significant implications across various industries and applications.
### Definition and Formula
The electrochemical equivalent of a substance can be defined using Faraday's laws of electrolysis. The first law states that the mass (\(m\)) of a substance deposited or dissolved at an electrode is directly proportional to the quantity of electric charge (\(Q\)) passed through the electrolyte:
\[
m = Z \cdot Q
\]
Where:
- \(m\) = mass of the substance (in grams)
- \(Q\) = electric charge (in coulombs)
- \(Z\) = electrochemical equivalent (in grams per coulomb)
### Units
- The unit of ECE is typically grams per coulomb (g/C), which indicates how many grams of a substance will be deposited or dissolved when one coulomb of electric charge is passed.
### Calculation of Electrochemical Equivalent
To calculate the electrochemical equivalent, you can use the following steps:
1. **Identify the Substance**: Determine the chemical involved in the electrolysis process.
2. **Determine the Valency**: Find the valency (\(n\)) of the substance. For instance, if you are working with copper ions (\(Cu^{2+}\)), the valency is 2.
3. **Molar Mass**: Find the molar mass (\(M\)) of the substance. For copper, \(M = 63.5 \, g/mol\).
4. **Use the Formula**: The electrochemical equivalent can be calculated using the formula:
\[
Z = \frac{M}{n \cdot F}
\]
Where:
- \(M\) = molar mass of the substance (g/mol)
- \(n\) = number of moles of electrons transferred per mole of substance (valency)
- \(F\) = Faraday's constant (\(F \approx 96500 \, C/mol\)), which is the charge of one mole of electrons.
### Example Calculation
Let's calculate the electrochemical equivalent of copper (\(Cu\)):
1. Molar mass of copper, \(M = 63.5 \, g/mol\)
2. Valency of copper, \(n = 2\) (since \(Cu^{2+}\) needs 2 electrons)
3. Using Faraday's constant, \(F = 96500 \, C/mol\)
Now, substituting these values into the formula:
\[
Z = \frac{63.5}{2 \times 96500} \approx 0.000329 \, g/C
\]
This means that approximately 0.000329 grams of copper will be deposited for every coulomb of charge passed.
### Applications
1. **Electroplating**: Understanding ECE helps in controlling the thickness of coatings applied during electroplating.
2. **Battery Technology**: It aids in calculating the amount of materials needed in batteries.
3. **Electrolysis Processes**: ECE is crucial in processes like electrolysis for separating elements or compounds.
### Conclusion
Electrochemical equivalent is a fundamental concept that bridges electrical and chemical phenomena, allowing for the quantitative analysis of reactions occurring during electrolysis. By knowing the electrochemical equivalent of a substance, one can accurately predict the mass of a material that will be produced or consumed in electrochemical processes, which has significant implications across various industries and applications.
**Electrochemical Equivalent (ECE)** is an important concept in electrochemistry, particularly in Class 12 Physics and Chemistry curriculums. It is a quantitative measure that relates the amount of substance deposited (or dissolved) during an electrochemical reaction to the quantity of electric charge that flows through the solution.
### Definition of Electrochemical Equivalent (ECE):
The **electrochemical equivalent** of a substance is defined as the **mass of the substance deposited or liberated at an electrode when one coulomb of electric charge passes through the electrolyte**. It is denoted by the symbol **Z** and measured in **kilograms per coulomb (kg/C)**.
### Formula for Electrochemical Equivalent:
The relationship between the electrochemical equivalent and other quantities can be given by:
\[
Z = \frac{M}{nF}
\]
Where:
- \( Z \) = Electrochemical equivalent (kg/C)
- \( M \) = Molar mass of the substance (in kilograms per mole)
- \( n \) = Valency (number of electrons involved in the reaction)
- \( F \) = Faraday’s constant (approximately \( 96500 \, C/mol \))
This formula shows how the electrochemical equivalent depends on the molar mass, the valency of the ion, and Faraday's constant.
### Faraday's Laws and Electrochemical Equivalent:
The concept of electrochemical equivalent is closely tied to **Faraday's Laws of Electrolysis**:
1. **Faraday's First Law** states that the mass of a substance deposited or liberated at an electrode during electrolysis is directly proportional to the amount of electric charge passed through the electrolyte.
\[
m \propto Q
\]
\[
m = Z \cdot Q
\]
Where:
- \( m \) is the mass of the substance deposited (in kilograms),
- \( Z \) is the electrochemical equivalent,
- \( Q \) is the electric charge (in coulombs).
2. **Faraday's Second Law** states that when the same amount of electric charge is passed through different electrolytes, the mass of the substance deposited is proportional to its electrochemical equivalent.
### Units of Electrochemical Equivalent:
Since **Z** is the mass deposited per unit of electric charge, its units are typically:
- **kg/C (kilograms per coulomb)** or
- **g/C (grams per coulomb)**.
### Example:
Suppose we want to find the electrochemical equivalent of silver (Ag). The molar mass of silver is 107.87 g/mol, and since silver has a valency of 1 (it forms Ag⁺ ions), we can calculate \( Z \) as:
\[
Z = \frac{M}{nF} = \frac{107.87 \times 10^{-3}}{1 \times 96500} \, \text{kg/C}
\]
\[
Z \approx 1.117 \times 10^{-6} \, \text{kg/C}
\]
This means that 1.117 × 10⁻⁶ kg (or 1.117 mg) of silver will be deposited when a charge of 1 coulomb is passed through a silver nitrate solution.
### Summary:
In simple terms, **electrochemical equivalent** tells us how much mass of a substance is deposited or released in an electrochemical reaction when a certain amount of electric charge flows through the electrolyte. It is a key concept in understanding how electric current interacts with chemical changes during electrolysis.
### Definition of Electrochemical Equivalent (ECE):
The **electrochemical equivalent** of a substance is defined as the **mass of the substance deposited or liberated at an electrode when one coulomb of electric charge passes through the electrolyte**. It is denoted by the symbol **Z** and measured in **kilograms per coulomb (kg/C)**.
### Formula for Electrochemical Equivalent:
The relationship between the electrochemical equivalent and other quantities can be given by:
\[
Z = \frac{M}{nF}
\]
Where:
- \( Z \) = Electrochemical equivalent (kg/C)
- \( M \) = Molar mass of the substance (in kilograms per mole)
- \( n \) = Valency (number of electrons involved in the reaction)
- \( F \) = Faraday’s constant (approximately \( 96500 \, C/mol \))
This formula shows how the electrochemical equivalent depends on the molar mass, the valency of the ion, and Faraday's constant.
### Faraday's Laws and Electrochemical Equivalent:
The concept of electrochemical equivalent is closely tied to **Faraday's Laws of Electrolysis**:
1. **Faraday's First Law** states that the mass of a substance deposited or liberated at an electrode during electrolysis is directly proportional to the amount of electric charge passed through the electrolyte.
\[
m \propto Q
\]
\[
m = Z \cdot Q
\]
Where:
- \( m \) is the mass of the substance deposited (in kilograms),
- \( Z \) is the electrochemical equivalent,
- \( Q \) is the electric charge (in coulombs).
2. **Faraday's Second Law** states that when the same amount of electric charge is passed through different electrolytes, the mass of the substance deposited is proportional to its electrochemical equivalent.
### Units of Electrochemical Equivalent:
Since **Z** is the mass deposited per unit of electric charge, its units are typically:
- **kg/C (kilograms per coulomb)** or
- **g/C (grams per coulomb)**.
### Example:
Suppose we want to find the electrochemical equivalent of silver (Ag). The molar mass of silver is 107.87 g/mol, and since silver has a valency of 1 (it forms Ag⁺ ions), we can calculate \( Z \) as:
\[
Z = \frac{M}{nF} = \frac{107.87 \times 10^{-3}}{1 \times 96500} \, \text{kg/C}
\]
\[
Z \approx 1.117 \times 10^{-6} \, \text{kg/C}
\]
This means that 1.117 × 10⁻⁶ kg (or 1.117 mg) of silver will be deposited when a charge of 1 coulomb is passed through a silver nitrate solution.
### Summary:
In simple terms, **electrochemical equivalent** tells us how much mass of a substance is deposited or released in an electrochemical reaction when a certain amount of electric charge flows through the electrolyte. It is a key concept in understanding how electric current interacts with chemical changes during electrolysis.