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Give Reasons Why In the Electroplating of an Article with Silver, the Electrolyte Sodium Argentocyanide Solution is Preferred Over Silver Nitrate Solution.

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Question

Give reasons why In the electroplating of an article with silver, the electrolyte sodium argentocyanide solution is preferred over silver nitrate solution.

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Solution

If silver nitrate solution is used directly instead of double cyanide of silver and sodium, the deposition of silver will be very fast and hence not very smooth and uniform.

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2015-2016 (March) Science Paper 2

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Name the following :

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Give one word or phrase for the following:

Electrolytic deposition of a superior metal on a baser metal.


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The following question relate to the electroplating of an article with silver.
 What should be the nature of the anode?


Element X is a metal with valency 2. Element Y is a non-metal with valency 3.
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Electroplating steel objects with silver involves a three-step process.

Step 1: A coating of copper is applied to the object.

Step 2: A coating of nickel is applied to the object.

Step 3: The coating of silver is applied to the object.

    1. A diagram of the apparatus used for step 1 is shown

      1. The chemical process taking place on the surface of the object is \[\ce{Cu^2+(aq) + 2e- ->Cu(s)}\]
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      2. Explain why the concentration of copper ions in the electrolyte remains constant throughout step 1.
  1. Give two changes which would be needed in order to coat nickel on to the object in step 2.
  2. Write down the reaction taking place at the positive electrode during step 3.

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