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Electroplating is a process of plating a layer of any metal on another material by passing an electric current.
- Electroplating process involves two electrodes, one is the anode (positive electrode) and the other is the cathode (negative electrode) through which the current passes and this takes place in a solution called an electrolytic medium.
- Its applications can be widely seen in polishing metal oxides and giving them gold coating.
- Rusting of iron could be prevented by coating iron with an electroplating process.
- Electroplating also improves the material’s properties by enhancing its strength, appearance, and other things.
Read More: NCERT Solutions for Class 8 Science Chemical Effects of Electric Current
Key Terms: Electroplating, Metals, Electrode, Anode, Cathode, Electrolyte Solution, Oxidation, Reduction
What is Electroplating Process?
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Electroplating is made up of two terms, ‘electro’ meaning electric current, and ‘plating’ means covering the outer area of some material with a thin layer of a different material.
- Electroplating can be defined as the process of plating a metal onto the other metal by passing an electric current in order to prevent mainly corrosion of metals and also for decorative purposes.
- Electroplating finds its uses in many industries like electronics, aviation, jewelry, toys, etc.
- The process of electroplating is performed in an electrolytic cell.
- This electrolytic cell has anode, cathode, and electrolyte solutions.
- The metal which is undergoing electroplating is connected to the cathode.
- The electrolyte has a salt solution of the metal and this electrolyte ionizes to give positively charged ions or metal ions which move toward another positively charged electrode (anode) for electroplating the object subjected to the process.
Electroplating
Reasons For Electroplating
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There are various reasons for performing electroplating. Some of them are listed below:
- To protect the objects from rusting or corrosion.
- To make the appearance of an object shiny or lustrous.
- To enhance mechanical or engineering features.
Anode and Cathode
- In the electroplating process, the current is provided from the external source. This process takes place in an electrolytic cell.
- The electrode which is connected to the negative terminal of the battery is referred to as the cathode while the one which is connected to the positive terminal of the battery is the anode.
- In the cathode, an electrochemical reduction reaction takes place.
- In the anode, an electrochemical oxidation reaction takes place.
- In the electroplating process, metal dissolved from the anode can be plated onto the cathode. Here, the anode is provided with direct current oxidizes and dissolves its metal atoms in the electrolyte solution.
- At the negative terminal, cathode, the dissolved metal ion from above, is decreased and the metal is placed on the product.
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Working of Electroplating
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Working of Electroplating can be understood through the example of a layer of gold to be electroplated on jewelry made of metal to enhance or beautify its appearance.
- Gold plating is connected to the positively charged electrode i.e., the Anode of the circuit, and the metallic jewelry is kept at the negatively charged electrode i.e., the cathode.
- Both are kept dipped in the electrolytic solution. At this stage, the current is supplied to the anode which in turn oxidizes the gold atoms and dissolves them into a solution.
- Once the gold gets dissolved, the dissolved ions at the cathode get plated on metallic jewellery.
Various other factors also influence the plating. These are:
- Voltage of current supplied.
- Chemical composition of the electrolytic solution.
- Temperature
- Time Taken
- The distance between two electrodes, anode, and cathode.
Uses of Electroplating
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Electroplating is used for enhancing the appearance of material but it also finds uses in other areas also. The main application of electroplating is to prevent metal from Corrosion. The plated layer through the electroplating process performs the function of shielding and protects the material from corrosion. Other applications of the electroplating process are:
- Improves thickness of the surface of the metal.
- Improves water resistance capacity.
- It minimizes friction.
- Improves uniformity of any surface.
- It enhances electrical conductivity.
Electroplated Items
Examples of Electroplating
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Some examples of electroplating are:
- Artificial gold and silver jewelry are prepared with the help of the electroplating process i.e., by electroplating silver or gold metals on less expensive materials.
- Iron is most important for building bridges, automobile parts, etc but by the time iron gets rusted and hence prevents rusting or Corrosion, zinc coating is electroplated on iron.
- Tin cans, which are often used for storing cold drinks, are made by electroplating tin on iron.
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Thing to Remember
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- Electroplating is a process of plating a layer of any metal on another material by passing an electric current.
- Electroplating is done in a medium called an electrolytic solution.
- In this process two electrodes are involved namely the anode and cathode.
- Anode is a positively charged electrode on which oxidation takes place.
- Cathode is a negatively charged electrode on which reduction takes place.
- It is useful in several ways like improving the thickness of the surface of the metal, water resistance capacity, minimizing friction, improving uniformity of any surface, etc.
Sample Questions
Ques. What is Electroplating? (2 Marks)
Ans. Electroplating can be defined as the process of plating a metal onto the other metal by passing an electric current in order to prevent mainly corrosion of metals and also for decorative purposes. The process of electroplating is performed in an electrolytic cell. This electrolytic cell has anode, cathode, and electrolyte solutions.
Ques. List some factors that affect the Electroplating Process. (2 Marks)
Ans. Factors that affect the electroplating process are
- Electrode surface area
- Temperature
- Distance between anode and cathode
- Voltage of supplied current
- Temperature
Ques. Differentiate between Anode and Cathode. (3 Marks)
Ans. The difference between an anode and a cathode is as follows:
| Anode | Cathode |
|---|---|
| Anode is referred to as a positively charged electrode. | Cathode is referred to as a negatively charged electrode. |
| At the anode, an oxidation reaction takes place. | At the cathode, a reduction reaction takes place. |
| In the anode, Electricity or current move into the anode | In a cathode, Electricity or current move out from the cathode |
| In a galvanic cell, the anode is negatively charged. | In a galvanic cell, the cathode is positively charged. |
Ques. Differentiate between Oxidation and Reduction. (3 Marks)
Ans. The difference between oxidation and reduction is as follows:
| Oxidation | Reduction | |
|---|---|---|
| Oxidation is an act of losing electrons. | Reduction is an act of gaining electrons. | |
| Oxidation helps to increase oxidation numbers. | Reduction helps to decrease oxidation number. | |
| Oxidation reaction releases energy. | Reduction stores energy. | |
| In oxidation, the removal of hydrogen groups takes place. | In reduction, the addition of hydrogen groups takes place. | |
| Examples of oxidizing agents are Ozone, Bleach, and peroxide. | Examples of reducing agents are Metals. | |
Ques. Give uses of the electroplating process. (3 Marks)
Ans. The uses of the electroplating process can be listed below:
- The electroplating process is mainly used on metals to enhance or beautify the features of the surface of any objects. This process is widely used to prevent the corrosion or abrasion of metals.
- Another prominent use of the electroplating process is on commercial goods like automobiles are electroplated to give them a smooth texture and appearance with a thin layer of chromium.
- The electroplating process is also used to coat a thin sheet of expensive and rare metals over that of cheaper metals.
Ques. What is the main principle behind Electroplating? (2 Marks)
Ans. Electroplating is a process of depositing one metal over the other in the presence of a salt solution. As the water molecules are released as the final product hence, electroplating is based on the theory of hydrolysis. Hydrolysis is a mechanism that aids the procedure of electroplating. The use of water in the process coating of the electrodes makes the process less harmful and more environmentally friendly.
Ques. Give the steps for the electroplating process. (3 Marks)
Ans. The steps of electroplating are listed below:
- Firstly an electric current is used which helps in reducing the positively charged ion (cations), of the dissolved metals at the cathode, which is a negatively charged electrode.
- This above mechanism through cathode and anode gives a lean coherent metal coating on the electrode.
- The process of electroplating is applied frequently at the times of electrical oxidation of the anions (negatively charged ions) on a solid substrate.
Ques. List the advantages of the electroplating process. (3 Marks)
Ans. The advantages of the electroplating process are
- It protects objects from corrosion and abrasion. Additionally, it also improves object shock protection and heat resistance.
- Electroplating processed objects minimizes friction on metals when rubbed against each other, so, it reduces scraping and heat generation. In fact, less friction also helps in less wearing and tearing down of objects, and hence the life of the object increases.
- The electroplating process improves the properties of metals or objects by enhancing magnetism, conductivity, and thickness.
- Electroplating also improves adhesion in objects.
Ques. List the disadvantages of the electroplating process. (3 Marks)
Ans. The disadvantages of the electroplating process are
- If the electroplating process is not done properly then it can produce hazardous wastes which are very harmful to the environment.
- The process of setting up electroplating is quite expensive as it involves buying metals, chemicals, and other costly equipment.
- Electroplating is a very time-consuming process.
Ques. Explain the Electroplating Process through an example. (3 Marks)
Ans. Electroplating can be understood with an example of a layer of gold to be electroplated on jewelry made of metal to enhance its appearance.
- Gold plating is connected to the anode of the circuit and the metallic jewellery is kept at the cathode.
- Both are kept dipped in an electrolytic solution and current is supplied to the anode that in turn oxidizes the gold atoms and dissolves them into solution.
- Once the metal gold gets dissolved, the dissolved ions at the cathode are plated on metallic jewellery.
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