⚡ Electrochemistry – Class 12 Notes
Electrochemistry is an important chapter in Class 12 Chemistry. It deals with the relationship between chemical reactions and electrical energy. In electrochemistry, chemical energy can be converted into electrical energy and electrical energy can also be used to drive chemical reactions. This chapter is important for board exams as well as competitive exams. 🔋
🔬 Electrochemical Cells
An electrochemical cell is a device that converts chemical energy into electrical energy through a redox reaction.
There are mainly two types of electrochemical cells:
- ⚡ Galvanic Cell (Voltaic Cell) – Converts chemical energy into electrical energy.
- 🔌 Electrolytic Cell – Uses electrical energy to drive chemical reactions.
A common example is the Daniell Cell, which consists of a zinc electrode and a copper electrode.
🔋 Components of an Electrochemical Cell
- 🔩 Anode – Electrode where oxidation takes place.
- ⚙️ Cathode – Electrode where reduction occurs.
- 🌉 Salt Bridge – Maintains electrical neutrality in the cell.
- ⚡ External Circuit – Allows the flow of electrons.
Electrons always flow from anode to cathode in an external circuit.
📊 Electrode Potential
Electrode potential is the tendency of an electrode to gain or lose electrons. It is measured as Standard Electrode Potential.
Standard conditions include:
- Temperature = 25°C 🌡️
- Pressure = 1 atm
- Concentration = 1 M
⚖️ Nernst Equation
The Nernst Equation is used to calculate electrode potential under non-standard conditions.
E = E° − (0.059 / n) log Q
Where:
- E = Cell potential
- E° = Standard cell potential
- n = Number of electrons transferred
- Q = Reaction quotient
⚡ Electrolysis
Electrolysis is the process in which electrical energy is used to carry out a chemical reaction. This process occurs in an electrolytic cell.
Common applications of electrolysis include:
- ⚙️ Electroplating of metals
- 🔋 Extraction of metals
- 🧪 Purification of metals
📐 Conductance of Electrolytic Solutions
Conductance measures the ability of a solution to conduct electricity.
- ⚡ Specific Conductance – Conductance of a unit volume of solution.
- 📊 Molar Conductivity – Conductance of solution containing one mole of electrolyte.
Molar conductivity increases with dilution because ions move more freely. 📈
🔢 Faraday’s Laws of Electrolysis
Faraday proposed two laws related to electrolysis.
First Law:
The mass of substance deposited during electrolysis is directly proportional to the quantity of electricity passed.
Second Law:
The masses of substances deposited by the same quantity of electricity are proportional to their chemical equivalent weights.
🎯 Importance of Electrochemistry
- 🔋 Used in batteries and fuel cells
- ⚙️ Helps in metal extraction and purification
- 🧪 Important in corrosion studies
- 🏭 Widely used in industrial processes
Understanding electrochemistry helps students learn how chemical reactions produce electricity and how electricity can drive chemical changes. Regular practice of concepts and numerical problems will help in scoring well in Class 12 Chemistry exams. 🚀