We use electricity to run different appliances or other things such as doorbells, heaters, bulbs, fans, and many more. The chemical effect of electricity can be explained on these devices as well, and there are many ways to define chemical effects of electric current in brief. These devices make use of various effects of electric current like the heating effect and magnetic effect. Its chemical effect is another often-used effect of electric current. When electricity is passed through some specific liquids, chemical changes take place. Some of these changes are quite important to us.
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How is it Possible to Pass Electricity Through a Liquid? Let Us Look at It
Let us put two electrodes in the liquid and apply a fixed voltage across them. In a circuit, an electrode is a conductor being in contact with a nonmetallic thing, like liquid or gas. The electrode which is connected to the battery's positive terminal is known as the anode, whereas the electrode connected to the negative terminal is known as the cathode.
During rainy seasons we are often told to stay away from the electric poles. If we ever wondered why it is so, as the water flows continuously, the insulator turns into a conductor. Resultantly, electricity can flow through our bodies.
Thermal and Chemical Effects of Electric Current
The thermal and chemical effects of electric current are described briefly below. Let us have a look at these two factors.
Chemical Effects of Electric Current
This is a chemical effect of electricity that can be explained in terms of chemical properties. We all know that when an electric current passes through a solution, it ionizes and breaks down into ions. This is because of the chemical reactions that happen when an electric current passes through a solution. The electric current and its chemical effects are given below to identify easily. Based on the electrodes used and the nature of the solution, the following effects can be noticed in the solution:
A Change in the colour of the solution
Metallic deposits on the electrodes
Production of bubbles or a release of gas in the solution
Thermal Effects of Electric Current
Some of the thermal effects of electric current are given below.
Heating Effect - Let us look at the electricity and its heating and chemical effects thoroughly. The electric current makes heating of the electrical equipment. For example, the filament in a bulb gets heated up because of the electric current and glows, therefore.
Mechanical Effect - electric current can lead to the generation of mechanical energy in appliances. For example, motors and fans work due to this effect.
Magnetic Effect - electric current can lift upward to the magnetic field of a substance, which is a well-known chemical effect of electricity.
Chemical Effect - electric current can lead to the production of chemical reactions or chemical energy.
Application of Chemical Effect of Electric Current
Extracting Metals from Their Ores
Pure metals are extracted from the metal ores by the electrolysis process. Electricity is passed via the metal ores, and the ores get broken down into an ionic lattice, and thereby the metal obtains separately. For example, metals like magnesium, aluminium, potassium, calcium, and sodium are obtained from their ores in this way, which is a widely accepted application of chemical effect of electric current.
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Purification of Metals
The electrolysis method is used to purify metal by separating it from the impurities. The impure metal can be used as an anode that dissolves in the electrolyte solution first and later deposits on the cathode in the pure form. The metal impurities remain in the electrolyte solution only. Metals like aluminium, copper, and zinc are purified in this way.
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Production of Compounds
This electrolysis method is used for the production of some compounds, such as sodium hydrochloride. It is the easiest application of chemical effect of electric current.
Decomposition of Compounds
The electrolysis method is used to decompose a compound into its constituents. For example, water is decomposed with the process of electrolysis to obtain oxygen and hydrogen.
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Electroplating
Electroplating is a process where a layer of one metal is coated with another metal using the electrolysis method.
Electroplating Process for a Silver Spoon with Gold
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To coat the silver spoon with gold, we select the metal's acidified solution to be coated (gold chloride with the hydrochloric acid) as an electrolyte and the article (silver spoon) to be electroplated is selected as a cathode.
Then, take a thick plate of the metal (gold plate) to be deposited as an anode.
Now, the silver spoon should be cleaned with a dilute acid solution to remove the oxide layer from its surface and then washed in running water until it is free from the acid.
Thus, the cleaned silver spoon is suspended in the acidified gold chloride solution (electrolyte) kept in a beaker.
Also, the thick plate of gold (selected as an anode) is suspended in the gold chloride solution.
The circuit is then completed using a battery and a key.
Let the current pass through it for around 15 minutes and then remove the electrodes from the solution.
Therefore, the silver spoon will look like a gold spoon.
Uses of Electroplating
Some famous uses of electroplating are given as,
This is the most extensive use of gold plating used on watch cases and jewellery.
Zinc coating prevents the corrosion of steel articles.
Chromium and nickel-coated articles are used in household appliances and automobiles.
FAQs on Chemical Effects of Electric Current
1. What are the chemical effects of electric current?
The passage of an electric current through a conducting liquid, known as an electrolyte, can cause chemical reactions. This phenomenon is called the chemical effect of electric current. Key examples of these effects include:
- The formation of gas bubbles on the electrodes (as in the electrolysis of water).
- The deposition of a thin layer of metal onto another object (electroplating).
- Noticeable changes in the colour of the conducting solution.
2. What is electroplating and where is it used in daily life?
Electroplating is a practical application of the chemical effect of current where a thin layer of a desired metal is deposited onto another material. This is done to prevent corrosion, improve appearance, or add specific properties. Common examples include:
- Chromium plating on bicycle handlebars and bath taps for a shiny, scratch-resistant finish.
- Zinc coating on iron objects (a process called galvanisation) to protect them from rusting.
- Gold or silver plating on less expensive metals to create affordable jewellery.
3. Why do we need to add a few drops of acid to distilled water for it to conduct electricity?
We add a few drops of acid (like sulphuric acid) because distilled water is a poor conductor of electricity as it lacks free ions. The acid dissolves in the water and provides charged particles called ions, which are necessary to carry the electric current. These ions make the solution conductive, allowing the chemical effect (electrolysis) to take place and split water into hydrogen and oxygen.
4. Why is an LED a better choice than a bulb for a conductivity tester?
An LED (Light Emitting Diode) is a better choice because it can light up even when a very weak electric current flows through it. Many common liquids, such as lemon juice or tap water, are weak conductors. The small current they allow to pass may not be strong enough to heat the filament of a standard bulb to the point of glowing. Since an LED is highly sensitive, it provides a more reliable test for a wider range of liquids.
5. How are the chemical effects of electric current different from its heating effects?
The key difference lies in the type of change produced and the materials involved. The heating effect is a physical change that occurs in all conductors (solids and liquids) where electrical energy is converted into heat due to resistance. In contrast, the chemical effect is a chemical change that occurs specifically in conducting liquids (electrolytes), causing substances to decompose or be formed.
6. How does passing an electric current through a conducting liquid actually cause a chemical reaction?
A conducting liquid, or an electrolyte, contains positively and negatively charged particles called ions. When electrodes connected to a battery are placed in the liquid, these ions are set in motion. Positive ions move to the negative electrode (cathode) and negative ions move to the positive electrode (anode). This movement of ions is the electric current. When the ions reach the electrodes, they can gain or lose electrons, which results in a chemical change, forming new substances like gases or layers of metal.
7. Is it safe to handle electrical appliances with wet hands? Explain the reason based on chemical effects of current.
No, it is extremely dangerous. While pure water is a poor conductor, the tap water we use contains dissolved salts and minerals. These impurities make the water a good conductor of electricity. When your hands are wet, the water creates a conductive path for the current to flow from the appliance through your body to the ground. This can result in a severe, and possibly fatal, electric shock.
8. What happens when electricity is passed through a copper sulphate solution?
When electric current is passed through a copper sulphate (CuSO₄) solution, it breaks down into positive copper ions (Cu²⁺) and negative sulphate ions (SO₄²⁻). The positive copper ions are attracted to the negative electrode (cathode) and get deposited on it as a layer of pure copper. This process is a clear demonstration of the chemical effect of current and is the fundamental principle behind electroplating and the refining of copper.
