Methods of Refining of Metals Video Lecture - Chemistry Class 12 - NEET

Ans. The purpose of refining metals is to remove impurities and improve the quality of the metal. This process is essential to obtain metals with desired properties for various industrial applications.

Ans. There are several methods used for refining metals, including: - Electrolytic refining: This method is used for refining copper, silver, and gold. It involves the use of an electrolyte and an electric current to dissolve impurities and separate the pure metal. - Distillation: Distillation is primarily used for refining mercury. It takes advantage of the metal's low boiling point to vaporize and then condense it, leaving impurities behind. - Zone refining: This method is used to purify semiconducting materials like silicon and germanium. It involves passing a molten zone through the material, causing impurities to move along with it and leaving behind a highly pure metal. - Cupellation: Cupellation is used to refine precious metals like gold and silver. It involves heating the metal in a controlled environment to oxidize impurities, which are then absorbed by a separate material called a cupel. - Miller process: The Miller process is commonly used to refine gold. It involves bubbling chlorine gas through a molten mixture of gold and impurities, resulting in the formation of gold chloride that can be easily separated.

Ans. Electrolytic refining works by using an electrolyte solution and passing an electric current through it. The impure metal is made the anode, and a pure metal sheet is used as the cathode. As the current passes through the electrolyte, metal ions from the anode dissolve into the solution, while pure metal ions from the cathode deposit onto it. This process allows the impurities to be separated from the metal, resulting in a refined product.

Ans. Zone refining offers several advantages, such as: - High purity: Zone refining can produce metals with extremely high purity levels, making it suitable for applications that require exceptional material quality, such as semiconductors. - Selective purification: This method allows for the selective purification of specific impurities. By controlling the movement of the molten zone, it is possible to remove impurities more effectively. - Minimal waste: Zone refining generates minimal waste compared to other refining methods since only a small portion of the material is affected by the purification process.

Ans. The Miller process is commonly used for refining gold. It involves bubbling chlorine gas through a mixture of gold and impurities, resulting in the formation of gold chloride. The gold chloride can then be easily separated, purified, and converted back into pure gold.