Which factor primarily determines the thickness of the metal coating deposited during an electroplating process?

• A. The shape of the electrodes used
• B. The total electric charge passed through the electrolyte
• C. The atmospheric pressure above the electroplating bath
• D. The color of the electrolyte solution

Answer: (B)

Verified step by step guidance

1. Understand that electroplating involves the deposition of metal ions from an electrolyte onto a cathode by passing an electric current through the solution.
2. Recall Faraday's laws of electrolysis, which state that the amount of substance deposited at an electrode is directly proportional to the total electric charge passed through the electrolyte.
3. Recognize that the thickness of the metal coating depends on the mass of metal deposited, which is related to the number of moles of metal ions reduced at the cathode.
4. Use the relationship: \(m = \frac{Q \times M}{n \times F}\), where \(m\) is the mass of metal deposited, \(Q\) is the total electric charge, \(M\) is the molar mass of the metal, \(n\) is the number of electrons exchanged per ion, and \(F\) is Faraday's constant.
5. Conclude that since the total electric charge \(Q\) directly affects the amount of metal deposited, it primarily determines the thickness of the metal coating during electroplating.