The silver plate is connected to the positive terminal and the spoon to the negative terminal.
Explanation
Electroplating is the process of depositing a layer of any desired metal on another material by means of electricity. It relies on the chemical effect of electric current (electrolysis), where ions move within an electrolyte solution to deposit metal onto a specific electrode.
Detailed Analysis:
For electroplating silver onto a copper spoon, the setup must ensure that silver ions are reduced and deposited onto the spoon while the silver source replenishes the solution.
- The Cathode (Negative Terminal): The object to be electroplated (the copper spoon) is connected to the negative terminal of the battery. Positive silver ions (Ag+) from the electrolyte are attracted to the negative terminal, where they gain electrons (reduction) and deposit as a layer of metallic silver on the spoon.
- The Anode (Positive Terminal): The metal to be deposited (the silver plate) is connected to the positive terminal. At the anode, silver atoms lose electrons (oxidation) and enter the solution as silver ions, maintaining the concentration of the electrolyte.
Therefore, the silver plate must be connected to the positive terminal, and the spoon must be connected to the negative terminal.
Key Takeaway:
In an electrolytic cell used for electroplating, the object to be plated is always made the cathode (connected to the negative terminal), and the source metal is made the anode (connected to the positive terminal).