Electric current has several effects when it flows through different substances. One of these effects is the chemical effect of electric current, which occurs when electricity passes through a conducting liquid. This process, known as electrolysis, leads to chemical reactions such as decomposition, deposition, or the formation of gases.
This chapter explains how electric current affects liquids, the process of electrolysis, and its applications in daily life.
1. Conductors and Insulators of Electricity
Not all substances allow electricity to pass through them. Based on their ability to conduct electricity, substances are classified into:
1.1 Conductors
- Materials that allow electric current to pass through them.
- Example: Metals (copper, aluminum, iron), saltwater, acids, and bases.
1.2 Insulators
- Materials that do not allow electricity to pass through.
- Example: Rubber, plastic, wood, distilled water.
2. Good and Poor Conductors of Electricity in Liquids
2.1 Good Conductors of Electricity (Electrolytes)
- Liquids that conduct electricity due to the presence of ions.
- Examples:
- Tap water (contains dissolved salts and minerals).
- Acidic and basic solutions (e.g., lemon juice, vinegar, saltwater).
- Solutions of salts in water (e.g., sodium chloride solution).
2.2 Poor Conductors of Electricity (Non-Electrolytes)
- Liquids that do not conduct electricity due to the absence of free ions.
- Examples:
- Distilled water (pure water does not conduct electricity).
- Alcohol and oil.
3. Chemical Effects of Electric Current
When electric current passes through a conducting liquid (electrolyte), chemical reactions occur at the electrodes. These reactions may include:
- Formation of gases (hydrogen and oxygen).
- Deposition of metal on electrodes.
- Change in color of the solution.
This phenomenon is called the chemical effect of electric current.
Example of a Simple Electrolytic Experiment
- Setup: Take a beaker with saltwater, insert two electrodes (carbon or metal rods) connected to a battery.
- Observation: Bubbles of hydrogen and oxygen gas form at the electrodes.
- Conclusion: Electric current causes a chemical change in the solution.
4. Electrolysis (Breakdown of a Compound by Electricity)
Electrolysis is the chemical decomposition of a substance using electricity.
4.1 Process of Electrolysis
- A conducting liquid (electrolyte) is taken in a container.
- Two electrodes (positive and negative) are placed inside the liquid.
- When electric current is passed, the liquid breaks down into simpler substances.
4.2 Important Terms in Electrolysis
| Term | Definition |
|---|---|
| Electrolyte | Conducting liquid that undergoes electrolysis. |
| Electrode | Rods/plates through which current enters or leaves the solution. |
| Anode (+) | Positively charged electrode. |
| Cathode (-) | Negatively charged electrode. |
| Ion | Charged particles in the electrolyte. |
| Deposition | Formation of a solid layer on the electrode. |
Example: Electrolysis of Water
- Water contains H₂O molecules.
- When current is passed, water splits into hydrogen (H₂) and oxygen (O₂) gases.
- Hydrogen collects at the cathode (-), and oxygen collects at the anode (+).
Reaction:
5. Applications of Chemical Effects of Electric Current
The chemical effect of electric current is widely used in industries and daily life.
5.1 Electroplating
- A process where a metal layer is deposited on another material using electrolysis.
- Used to coat iron with zinc (galvanization) or gold plating on jewelry.
- Example: Silver and gold plating on ornaments.
5.2 Electrorefining of Metals
- Purification of impure metals using electrolysis.
- Used for refining copper, aluminum, and gold.
5.3 Extraction of Metals
- Metals like sodium, aluminum, and copper are extracted from their ores using electrolysis.
5.4 Electrolysis in Daily Life
- Production of chlorine, hydrogen, and oxygen gases.
- Electrolysis of brine (saltwater) produces chlorine gas, which is used in disinfectants.
6. Factors Affecting the Chemical Effects of Electric Current
Several factors influence the chemical changes during electrolysis:
- Type of Electrolyte – Stronger electrolytes cause faster reactions.
- Type of Electrodes – Some electrodes react, while others remain unchanged.
- Strength of Current – More current results in faster chemical changes.
- Duration of Electrolysis – The longer the current flows, the more chemical effects occur.
7. Electroplating Process
Electroplating is used to coat a thin layer of one metal over another.
Steps of Electroplating
- Take a solution of the metal to be coated (e.g., silver solution).
- Connect the object to be coated (cathode, -).
- Connect the metal that will coat (anode, +).
- Pass electric current for some time.
- The metal deposits on the object.
Examples of Electroplating
- Iron objects electroplated with zinc (prevents rusting).
- Jewelry electroplated with gold or silver.
- Tin-plated food cans (prevents corrosion).
8. Differences Between Good and Poor Conductors of Electricity
| Type | Examples | Why? |
|---|---|---|
| Good Conductors | Saltwater, acid solutions, metals | Contain free-moving ions |
| Poor Conductors | Distilled water, alcohol, oil | Do not have free ions |
9. Safety Precautions While Using Electrolysis
- Do not touch electrical wires with wet hands.
- Use only recommended voltage for electrolysis experiments.
- Ensure the proper disposal of chemical waste.
- Avoid using corrosive electrolytes without safety measures.
Conclusion
The chemical effects of electric current play an essential role in science and industry. Through electrolysis, various useful processes like electroplating, metal refining, and extraction are carried out. Understanding these effects helps in appreciating the role of electricity in our daily lives.
FAQs on Chemical Effects of Electric Current
1. What is the chemical effect of electric current?
The chemical effect of electric current refers to chemical changes in a liquid when electricity is passed through it, such as decomposition, deposition, and gas formation.
2. What is electrolysis?
Electrolysis is the process of chemical decomposition of a substance by passing an electric current.
3. What are electrolytes?
Electrolytes are liquids that conduct electricity due to the presence of free ions.
4. What is electroplating?
Electroplating is a process of coating one metal over another using electrolysis.
5. What are good conductors of electricity in liquids?
Saltwater, acids, and bases are good conductors as they contain free ions.
6. Why is distilled water a poor conductor of electricity?
Distilled water lacks free ions, making it a poor conductor.
7. What are the applications of electrolysis?
Electrolysis is used in metal refining, electroplating, extraction of metals, and gas production.