William Nicholson, a British chemist, demonstrated that oxygen and hydrogen bubbles are formed when the electrodes are submerged in water and a current is passed through the water. He noticed that the hydrogen bubbles were formed at the electrode connected to the negative terminal while the oxygen bubbles were formed at the electrode connected to the positive terminal.
William Nicholson discovered the electrolysis of water
When an electric current flows through a conducting solution, chemical reactions take place in the solution. This is called the chemical effect of electric current. Some of the chemical effects of electric current are as follows:
- Gas Bubbles are formed at electrodes
- Metals are deposited on electrodes
- Change of colour of the solution.
Do liquids conduct electricity?
All liquids do not conduct electricity. Nevertheless, some liquids are good conductors of electricity while others are bad conductors of electricity. Water with dissolved salts and minerals is a good conductor of electricity while distilled water is a bad conductor of electricity.
What happens when an electric current passes through a conducting solution?
The passage of electric current through a conducting solution results in chemical reactions. As a result, bubbles of gas may be deposited on the electrodes. Deposits of metal may be seen on electrodes. Changes in the colour of solutions may occur. The reaction would depend on what solution and electrodes are used.
When electricity is passed through water mixed with different substances, the constituents break into negative and positive ions. These ions pass an electric current through them. The more the number of ions, the better the conductor of electricity it is.
Experiment to Demonstrate the Conduction of Electricity in Liquids
- Construct a circuit with a cell, connecting wires and an LED.
- Insert the free ends of the wire into a beaker of water without touching each other.
- If the LED glows, then it indicates that the liquid is a conductor of electricity, and if it doesn’t glow, it is an indication that the liquid doesn’t conduct electricity.
- The liquid is a good conductor of electricity if the brightness of the LED is high.
- Likewise, if the brightness of the LED bulb is low, then the liquid is a bad conductor of electricity.
Applications of Chemical Effects of Electric Current
Electroplating
Electroplating is a process where a layer of metal is deposited on another material with the help of electricity. Based on the application, the right electrodes and electrolytes must be chosen. To deposit gold over a material, an electrolyte containing gold must be chosen. Out of the two electrodes, one electrode should be of gold, and the other electrode needs to be a material on which gold is coated.
Electroplating of Copper on Brass
While coating copper over brass, you need a copper electrode and a brass electrode and any solution containing copper, such as copper sulphate solution. The copper electrode is made anode, and the brass electrode is made the cathode. When current is passed through the copper sulphate solution, it breaks down into ions. The copper ions with a positive charge get attracted to the brass electrode, and the sulphur ions with a negative charge get attracted to copper electrode. The amount of time taken for the completion of the process depends upon the strength of the being passed through the circuit and the concentration of the solution.
Applications of Electroplating
- Electroplating is used in imitation jewellery which is made by applying a layer of gold or silver.
- Parts of a bicycle and motorbike are chrome plated through electroplating.
- Tin cans are made by electroplating tin on iron.
- Beams of bridges and electric poles are electroplated with zinc.
- Anodizing and chrome plating prevent corrosion.
Extracting Metals from their Ores
Electroplating is used to extract metals from metal ores. When electricity is passed through metal ores, they get broken down into ionic lattices. This way, the metals are extracted separately. Metals such as sodium, calcium, potassium, aluminium and magnesium are obtained from their ores using this method.
Purification of metals
Electrolysis is used in the purification of metals by extracting impurities from them. The impure metal is used as an anode in the process and is dissolved in the electrolyte solution. The metal ions are deposited on the cathode during the process, and a pure form of metal is obtained here. The impurities remain in the electrolyte solution. Metals such as zinc, copper, aluminium and copper are purified this way.
Production of Compounds
Electrolysis is helpful in producing some compounds, such as sodium hypochlorite.
Decomposition of Compounds
Electrolysis is used to decompose a compound into its constituents. Water can be decomposed into hydrogen and oxygen through electrolysis.
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