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प्रश्न
How is impure copper purified by electrolysis ? Explain.
उत्तर
Electrolytic refining is used for the purification of copper. In this case
Cathode : Pure copper strip
Anode : Impure copper
Electrolyte : A solution of copper sulphate and dilute sulphuric acid.
When the current is passed through the electrolyte , the copper ions of the copper sulphate solution are attracted to the cathode where they gain electrons and are deposited on pure copper strips. The impure copper loses electrons and passes into solution as soluble copper ions.
At Cathode : Cu+2 + 2e- → Cu
At anode : Cu + 2e- → Cu+2
APPEARS IN
संबंधित प्रश्न
Name the metallic ions that should be present in the electrolyte when an article made of copper is to be electroplated with silver.
Copy and complete the following table:
| Anode | Electrolyte | |
| Purification of copper |
How would you change Cu2+ ion to Cu?
Explain the terms : Electro refining
The following question relate to the electroplating of an article with silver.
What should be the nature of the anode?
A solution of silver nitrate is a good electrolyte but is not used for electroplating an article with silver.
Draw a labelled diagram to show how iron is electroplated with copper.
Describe what happens to the iron object and the copper rod.
What ions must be present in a solution used for electroplating a particular metal?
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.
-
- A diagram of the apparatus used for step 1 is shown
- The chemical process taking place on the surface of the object is \[\ce{Cu^2+(aq) + 2e- ->Cu(s)}\]
What is the observation seen on the surface of the object? - Explain why the concentration of copper ions in the electrolyte remains constant throughout step 1.
- The chemical process taking place on the surface of the object is \[\ce{Cu^2+(aq) + 2e- ->Cu(s)}\]
- A diagram of the apparatus used for step 1 is shown
- Give two changes which would be needed in order to coat nickel on to the object in step 2.
- Write down the reaction taking place at the positive electrode during step 3.
