Write the cathode and anode reaction during electrorefining of copper
During electrorefining of copper, the cathode reaction and anode reaction can be represented as follows:
Cathode reaction: Cu2+(aq) + 2e- → Cu(s)
Anode reaction: Cu(s) → Cu2+(aq) + 2e-
At the cathode, copper ions in the aqueous solution gain electrons and are reduced to form solid copper metal. This process helps to purify the copper.
At the anode, solid copper metal is oxidized, losing electrons to form copper ions in the aqueous solution. This helps to maintain the overall charge balance in the electrorefining process.
During electrorefining of copper, copper impurities from the anode are removed through electrolysis. The copper anode is dissolved and copper is deposited on the cathode. The overall reaction can be written as:
At the anode: Cu(s) -> Cu2+(aq) + 2e-
At the cathode: Cu2+(aq) + 2e- -> Cu(s)
In summary, at the anode, copper atoms are oxidized to Cu2+ ions, releasing two electrons into the solution. At the cathode, Cu2+ ions are reduced, accepting two electrons and depositing copper metal.
During electrorefining of copper, impure copper anodes are used. The anode reaction involves the oxidation of impurities present in the copper anode. These impurities can include elements such as iron, zinc, and sulfur.
The anode reaction can be represented as follows:
For the oxidation of copper:
Cu(s) → Cu2+(aq) + 2e-
For the oxidation of impurities like iron:
Fe(s) → Fe2+(aq) + 2e-
For the oxidation of impurities like zinc:
Zn(s) → Zn2+(aq) + 2e-
For the oxidation of impurities like sulfur:
S(s) → S2-(aq) + 2e-
On the other hand, pure copper cathodes are used, which serve as the site for the reduction reaction. The reduction reaction involves the deposition of pure copper onto the cathode surface.
The cathode reaction can be represented as follows:
Cu2+(aq) + 2e- → Cu(s)
Overall, the electrorefining process helps in purifying impure copper by oxidizing the impurities at the anode and depositing pure copper onto the cathode.