Please give better explanation.
Question from Ch-15 ( Chemical effects of electric current ) Class 8th
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Answers
→Electroplating is the process of plating one metal onto another by hydrolysis, most commonly for decorative purposes or to prevent corrosion of a metal.
→ Electroplating allows manufacturers to use inexpensive metals such as steel or zinc for the majority of the product and then apply different metals on the outside to account for appearance, protection, and other properties desired for the product. The surface can be a metal or even plastic.
A few metals used for electroplating are :
Chromium: Chromium has a shiny appearance, does not corrode and resists scratches. However chromium is expensive and it may not be to make the whole object out of chromium. So the object is made from a cheaper metal and only a coating of chromium over it is done.
Zinc : Zinc electroplating is often chosen when cost is a primary concern. One key advantage of plating with zinc is its compatibility with just about any type of metal. Zinc can also produce a wide range of surface colors. In its natural state, zinc will provide a silvery-gray finish, although colors such as blue, yellow and black can be achieved.
Important zinc plating benefits include excellent adhesion and its resistance to hydrogen embrittlement. Because of its superior adhesive capabilities, zinc plating is sometimes used to provide a base coat prior to painting. Zinc plating is frequently used in the manufacturing of washers, bolts, nuts, transmission components, armored personnel carriers and tanks.
Tin : The electroplating of tin, or “tinning,” is often viewed as a cost-effective alternative to plating with more expensive materials such as gold, silver or palladium. Tin’s relatively low cost and abundant supply makes it a popular choice for many different industrial applications, such as the manufacturing of electronic parts and components, hardware products, fasteners, screws, nuts and bolts.
Key tinning benefits include excellent resistance against surface corrosion, high solderability and good contact resistance.
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The passage of an electric current through a conducting liquid causes chemical reaction.
Most liquids that conduct electricity are solution of acids, bases and salts.
Painting also prevent corrosion as it add only one or more layer to the surface of material. Electroplating creates much stronger bond with the surface of materials to prevent it from corrosion for a long time and gives a shiny appearance of metal.