How Does Electrolysis Lead to Electroplating?
Electrolysis is said to be a process which uses an electrical current which is directed to break chemical compounds, while Electroplating is a process that uses electrical current to reduce the dissolved metal like cations so that they form a metal which is coherent coating on an electrode.
The word “electrolysis” was introduced by Michael Faraday in the 19th century. In chemistry we have seen that electrolysis is a method that uses a DC to drive a nonspontaneous reaction which is the chemical reaction. This technique is commercially significant as a stage in the separation of elements from naturally occurring sources such as ores, using an electrolytic cell.
Electrolysis Process
The fundamental process of electrolysis is the interchanging of atoms and the ions by the addition or removal of electrons from the external circuit.
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The Ionic compounds that contain the charged particles are called ions. For example we can say that Sodium Chloride basically contains positively charged Sodium ions and they are charged negatively with chlorine ions.
The ions which must be free to move in order to start the process of electrolysis. When a substance which is ionic is dissolved in water or we can say melted then the ions are free to move. During the process of electrolysis the positively charged ions move to the electrode which is a negative electrode and they are charged negatively ions move to the positive electrode. Then the charges which are positively ions that receive the electrons and are negatively charged ions lose electrons. Both the products that are of the dissociation get collected at the point of electrodes.
For instance we can say that if electricity is passed through the molten sodium chloride then we can notice that the sodium chloride is broken into sodium and chlorine. And they are collected at their own respective electrodes. The metals that get precipitated and then the gases which escape from them. This ability which is to break down substance with a current is used in many ways.
The process of Electrolysis is widely used for electroplating.
Define Electrolysis
There's no such thing as alchemy which is changing magically common chemical elements that are into valuable and rare ones but the process of electroplating is possibly the next best thing. The idea is to use electricity to coat a relatively metal which is mundane such as copper which is with a thin layer of another metal which is more precious. such as silver or gold.
The process of electroplating that has lots of other uses which is besides making cheap metals look expensive. We can say that the use of all these things is to make things that are rust-resistant. For example we can say that to produce a variety that is of useful alloys like bronze and brass and even which is to make plastic look like metal. A question arises: how does this amazing process work? Let's take a closer look about it in this article.
Electroplating Process
The process of electroplating is very similar to electrolysis by using electricity to split up a chemical solution. which is said to be the reverse of the process by which batteries produce electric currents. All these things are said to be given examples of electrochemistry, the chemical reactions caused by or producing electricity that give scientifically or we can say the industrially useful end-products.
First of all we have to choose the right electrodes and electrolyte that is by figuring out the chemical reaction or we say that the reactions you want to happen when the electric current is switched on. The metal or the atoms that plate our object come from out of the electrolyte. So if we want to plate copper that is something we need an electrolyte made from a solution of a salt of the copper while for gold plating we need a gold-based electrolyte and so on.
Next we can say that to ensure the electrode we want to plate is completely clean. Otherwise we can say that when metal atoms which are from the electrolyte are deposited onto it. They actually won't form a good bond and they may simply rub off again over it. Generally we can say that cleaning is done too by dipping the electrode into an acid which is very strong or we can say an alkaline solution or by briefly connecting the circuit which is electroplating in reverse. If the electrode that we have discussed is really clean and the atoms from the plating metal bond to it effectively by joining very strongly onto the edge which is outside of its crystalline structure.
FAQs on Electrolysis and Electroplating Explained for Students
1. What is the basic principle of electrolysis?
Electrolysis is a process that uses a direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. The core principle involves passing this current through a substance called an electrolyte (an ionic compound in a molten state or dissolved in a suitable solvent). This causes the positively charged ions (cations) to move to the negative electrode (cathode) and the negatively charged ions (anions) to move to the positive electrode (anode), where they undergo chemical changes like reduction and oxidation.
2. What is electroplating and what is its main purpose?
Electroplating is a specific application of electrolysis where a thin, protective, or decorative layer of a metal is deposited onto the surface of another object. In this process, the object to be plated is made the cathode (negative electrode) in an electrolytic cell. The main purposes of electroplating are:
- Protection: To prevent corrosion or rusting of the underlying metal (e.g., chrome plating on car parts).
- Aesthetics: To give an object a more attractive appearance (e.g., silver or gold plating on jewellery).
- Improving Properties: To enhance surface properties like hardness, wear resistance, or electrical conductivity.
3. What is the key difference between electrolysis and electroplating?
The main difference is that electrolysis is a broad chemical process, while electroplating is a specific use of that process. Electrolysis refers to any procedure that uses electricity to decompose a compound. Electroplating is one such procedure, specifically designed to coat an object with a metal. In simple terms, all electroplating is a form of electrolysis, but not all electrolysis results in electroplating (for example, the electrolysis of water to produce hydrogen and oxygen gas).
4. How does the process of electrolysis work in an electrolytic cell?
The process of electrolysis in an electrolytic cell follows these key steps:
- An electrolyte (e.g., molten salt or an aqueous solution of a salt) is placed in a container.
- Two electrodes, an anode (positive) and a cathode (negative), are immersed in the electrolyte and connected to a direct current (DC) power source.
- When the current is turned on, the cations (positive ions) in the electrolyte are attracted to the cathode, where they gain electrons (reduction).
- Simultaneously, the anions (negative ions) are attracted to the anode, where they lose electrons (oxidation).
- This flow of ions and electrons completes the circuit and causes a chemical decomposition of the electrolyte.
5. What are some common real-world examples of electrolysis and electroplating?
Both processes have significant real-world applications.
Examples of Electrolysis:
- Extraction of Metals: Highly reactive metals like aluminium and sodium are extracted from their ores using electrolysis.
- Purification of Metals: Copper is purified to a very high degree (99.99%) using electrolysis for use in electrical wiring.
- Production of Chemicals: It is used to produce chlorine gas and sodium hydroxide (NaOH) from brine (a salt solution).
- Jewellery: Cheaper metals are coated with gold or silver to make affordable fashion jewellery.
- Automotive Parts: Bumpers and rims are chrome-plated for a shiny finish and rust protection.
- Cutlery: Spoons and forks are often electroplated with silver.
6. Why can’t alternating current (AC) be used for electrolysis or electroplating?
Alternating current (AC) cannot be used because it constantly reverses its direction and polarity. For electrolysis to work, there must be a continuous, one-way migration of ions to specific electrodes. If AC were used, the anode and cathode would constantly switch roles. An ion moving towards one electrode would be forced to reverse its direction in the next half-cycle. In electroplating, this would mean any metal deposited in one moment would be stripped away in the next, resulting in no net coating. Therefore, a stable direct current (DC) is essential.
7. What factors decide which ion gets discharged at an electrode during electrolysis?
Several factors determine which ion is preferentially discharged at an electrode, especially when multiple types of ions are present (e.g., in an aqueous solution):
- Position in the Electrochemical Series: Cations of less reactive metals (like copper or silver) are discharged more easily than those of more reactive metals (like sodium or potassium).
- Concentration of Ions: If an ion is present in a very high concentration, it may be discharged in preference to an ion that is lower in the electrochemical series.
- Nature of the Electrode: The electrode material can be inert (like platinum or graphite), meaning it doesn't participate in the reaction, or active, where the electrode itself can dissolve and take part in the reaction.
8. Can non-metallic objects like plastic be electroplated?
Yes, non-metallic objects like plastic can be electroplated, but not directly. Since electroplating requires the object to conduct electricity to act as a cathode, a non-conductive surface must first be made conductive. This is typically done by coating the object with a thin layer of a conductive material, such as graphite-based paint or a layer of metal applied through a different process (like electroless plating). Once the surface is conductive, the object can be electroplated using the standard electrolytic process.
