Electrochemistry is the branch of chemistry that studies the relationship between chemical reactions and electricity. It can be understood in two major ways:
1. Chemical reactions generating electricity
- Example: Electrochemical cells (batteries), where chemicals react to produce electrical energy.
2. Electricity driving chemical reactions
- Example: Electrolysis, where electricity enables reactions that would not occur naturally.
Flow of Electrons
- In metals, electrons are free to move from one atom to another.
- The flow of these free electrons or ions constitutes an electric current.
Methods of Generating Electricity
1. Frictional Method
- Produces static electricity.
- Example: When a comb or plastic pen is brushed vigorously over hair, it generates charges that can attract small pieces of paper.
2. Chemical Method
- Involves chemical reactions (e.g., in batteries) that generate electricity.
Current Electricity
- Consists of fast‑moving streams of negatively charged electrons.
- Travels in a continuous path (circuit).
- Maintained by a potential difference between two points, causing sustained electron flow along electrodes.
Chemical Effects of Electricity
- Some materials undergo chemical changes when an electric current passes through them (in solution or molten state).
- Metals allow electricity to pass without undergoing a chemical change.
- Evidence of current flow is seen when an electric bulb lights up in the circuit.
Dual Role of Electricity and Chemistry
- Electrolysis: Electricity brings about chemical reactions.
- Electrochemical Cells: Chemical reactions generate electricity.
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