Chemical Effects & Conducting Liquids
📚 Topic Overview: Electricity – Chemical Effects & Conducting Liquids
This lesson explains how electric current interacts with liquids,
why some liquids conduct electricity well and others do not,
and how electroplating is used in daily life and industries.
Concepts are presented with examples, comparison tables, applications, and memory aids.
1. Chemical Effects of Electric Current
Concept / Theory
When electric current passes through certain liquids, they undergo chemical changes.
This is known as the chemical effect of electric current.
Common chemical effects include:
- Bubble formation (gas released)
- Change in colour of solution
- Metal deposition on electrodes
- Formation of smell or heat
Analogy / Example
- Just like heating milk changes its state, electric current can change chemicals in a liquid.
Classification Table
| Observation | Indication |
|---|---|
| Bubbles appear | Gas is formed |
| Colour changes | Chemical reaction occurs |
| Metal deposits | Metal ions move and coat the electrode |
Conversions / Notes
- Electricity → Chemical change
- Higher concentration = stronger chemical effect
| Keyword |
|---|
| Chemical Effect |
| Electrolyte |
| Electrode |
| Ions |
Electric water purifiers remove impurities using chemical effects produced by electric current.
Pure water never shows chemical effects. Only liquids with dissolved salts or acids show reactions.
2. Good / Poor Conducting Liquids
Concept / Theory
Liquids differ in how easily they allow electricity to pass.
Good conductors allow electric current to pass easily,
while poor conductors do not.
Comparison Table
| Good Conducting Liquids | Poor Conducting Liquids |
|---|---|
| Salt water | Distilled water |
| Lemon juice | Oil |
| Acidic solutions | Sugar solution (weak conductor) |
Analogy
- Salt water acts like a wide open highway for current; oil acts like a blocked road.
Notes
- Impurities increase conductivity.
- Purer liquids → lower conductivity.
| Keyword |
|---|
| Conductor |
| Insulator |
| Solution |
| Impurities |
Farmers test bore water by measuring how well it conducts electricity to estimate mineral content.
Distilled water is always a poor conductor because it contains no minerals or salts.
3. Electroplating
Concept / Theory
Electroplating is the process of depositing a thin layer of metal onto another object using electric current.
It uses the chemical effect of electricity.
Steps in Electroplating
- The object to be coated is connected to the negative terminal (cathode).
- The metal used for coating is connected to the positive terminal (anode).
- Both are dipped in a salt solution of the coating metal.
- Electric current is passed → metal atoms deposit on the object.
Comparison Table
| Metal Used | Purpose |
|---|---|
| Silver | Jewellery coating |
| Chrome | Bathroom fittings, bike parts |
| Zinc | Rust protection |
| Keyword |
|---|
| Electroplating |
| Anode |
| Cathode |
| Deposition |
Gold-plated ornaments look like pure gold but use much less gold because a thin layer is electroplated.
The object that receives the coating is always connected to the negative terminal (cathode).
Memory Formula Sheet
- Cathode = Negative = Receives coating
- Anode = Positive = Loses metal
- Electrolyte = Metal salt solution
Exam Tips & Tricks
- Distilled water = always poor conductor
- Bubble formation = chemical effect
- Electroplating = coating using electricity
- Impurities increase conductivity