Question

Write down applications of electrolysis with examples.

Short answer

Answer: The main applications of electrolysis are extraction of metals, electroplating, production of gases, and electrorefining. Examples for each application include: 1. Extraction of Metals - Aluminum is extracted from bauxite (2Al2O3 -> 4Al + 3O2). 2. Electroplating - Gold plating is used on jewelry for a gold appearance at a lower cost. 3. Production of Gases - Hydrogen and oxygen are produced from water (2H2O -> 2H2 + O2). 4. Electrorefining - Purifying copper using impure copper as the anode and pure copper as the cathode in a copper sulfate solution.

Step-by-step solution

Introduction to Electrolysis

Electrolysis is a process whereby an electric current is passed through a substance, causing a chemical change. This process is used to separate the elements in a compound or to decompose a chemical substance. Electrolysis has various applications in everyday life and industry.

Application 1: Extraction of Metals

One main application of electrolysis is the extraction of metals from their ores. For example, aluminum is extracted from its ore, bauxite, by electrolysis. In this process, aluminum oxide is dissolved in molten cryolite, and a direct current is passed through the resulting solution. This causes aluminum ions to migrate to the cathode, where they are reduced and deposited as aluminum metal. Example: Extraction of Aluminum from Bauxite: - 2Al_2O_3 -> 4Al + 3O_2

Application 2: Electroplating

Electroplating is another widely used application of electrolysis. Electroplating involves depositing a thin layer of metal onto another metal surface. This is done to improve the appearance, prevent corrosion, or increase the durability of the material. For example, gold plating is used on jewelry to give it a gold appearance at a lower cost. Example: Gold Plating: In this process, the metal piece to be plated acts as the cathode, while a gold electrode acts as the anode. Both are submerged in a gold salt solution. When the electric current is applied, gold ions migrate from the gold electrode to the metal piece being plated.

Application 3: Production of Gases

Electrolysis is often used to produce gases, like hydrogen and oxygen, from water. This can be a large-scale industrial process, as in the production of hydrogen for fuel cells, or a smaller-scale process for specific applications like the generation of oxygen required for divers to breathe underwater. Example: Production of Hydrogen and Oxygen from Water: - 2H_2O -> 2H_2 + O_2

Application 4: Electrorefining

Electrorefining is a process that uses electrolysis to purify metals, such as copper, gold, and silver. The impure metal is used as the anode, and a pure metal electrode is used as the cathode. When an electric current is applied, the impurities remain in the electrolyte or fall to the bottom of the cell as a sludge, while the pure metal ions are deposited onto the cathode. Example: Electrorefining of Copper: - Impure copper is placed at the anode, and pure copper is placed at the cathode. The electrolyte is a copper sulfate solution. Copper ions are transferred from the impure copper anode to the pure copper cathode, leaving impurities behind. These are just a few examples of the numerous applications of electrolysis in various industries and everyday life.

Key concepts

Extraction of Metals

The extraction of metals through electrolysis is a fundamental industrial process. To grasp how this works, imagine needing to extract a metal like aluminum from its bauxite ore. What happens here is a fascinating interplay between chemistry and electricity.

The aluminum oxide from bauxite is first dissolved in a substance called cryolite. When an electric current passes through, it splits the aluminum oxide into aluminum and oxygen. The aluminum ions are drawn toward the negative electrode (the cathode) and reduced to form pure aluminum metal.

This method isn't limited to aluminum; it's applied to several other metals as well. It's a critical process because it allows us to obtain pure metals that are essential for a wide range of products, from the pots and pans in your kitchen to the components of your smartphone.

Electroplating

Electroplating involves coating an object with a layer of a different metal, and electrolysis is the invisible craftsman behind this transformation. Think of it like giving a metal item a new outfit that isn't just for looks – it offers protection too.

For instance, with gold plating, items are submerged in a solution containing gold ions. The item to be plated acts as the cathode, and when the current flows, those gold ions venture over to the cathode and adhere to the surface. Jewelry, electronic components, and even bathroom fixtures are commonly electroplated not only to improve their appearance but also to enhance their resistance to corrosion and wear.

Production of Gases

Electrolysis isn't all about metals; it also enables us to harvest gases like hydrogen and oxygen from water. Splitting H2O might seem like magic, but it's all down to electric current.

When water undergoes electrolysis, hydrogen gas bubbles up at the cathode, while oxygen appears at the anode. This simple reaction has monumental implications, especially in the quest for clean energy solutions. Hydrogen, obtained through this process, is eyed as a potential eco-friendly fuel of the future. Meanwhile, oxygen generated this way has important uses, including providing life support in submarines and space vessels.

Electrorefining

Electrorefining is a purification parade led by electrolysis, where metals like copper, silver, and gold get to shed their impurities and shine bright. Impure metal is placed as the anode in an electrolyte solution, with a strip of the pure metal serving as the cathode.

When the current flows, pure metal ions travel from the anode to the cathode, leaving the less noble elements behind or at the bottom as waste. What's left at the cathode is a higher purity metal, ready for use in high-tech equipment, wiring, and jewelry. This method isn’t just effective; it's also crucial for recycling metals and minimizing waste, helping us keep pace with sustainable development.