1/9/2024 0 Comments Copper coinsYounger students might want to have their own coins plated. Place a small piece of zinc foil in the liquid as a substitute for the powder. If the mixture of sodium zincate solution and zinc is cloudy, allow to cool, and then filter off the zinc to leave a clear filtrate. It may be sensible to carry out a trial experiment before performing the demonstration in front of an audience. Allow the coin to cool and show it to the audience.Overheating will cause the coin to tarnish. Turn the coin so that both sides are heated equally. Using tongs or forceps, hold the plated coin in the upper part of a roaring Bunsen flame for a few seconds until the surface turns gold.Show the ‘silver’ coin to the audience.Remove the plated coin with tongs or forceps and rinse it under running tap water to remove traces of sodium hydroxide and sodium zincate.Leaving the coin too long may cause lumps of zinc to stick to it. Leave the coin until it is plated with a shiny coat of zinc.If necessary use a glass rod to move the coin until this is so. ![]() The coin must make contact with the powdered zinc at the bottom of the solution. ![]()
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