What substance is produced at the cathode during the electrolysis of molten calcium bromide (CaBr₂)? Assume standard conditions.

• A. Hydrogen gas (H₂)
• B. Bromine gas (Br₂)
• C. Calcium metal (Ca)
• D. Calcium bromide (CaBr₂)

Answer: (C)

Verified step by step guidance

1. Identify the components of molten calcium bromide (CaBr₂). It dissociates into calcium ions (Ca²⁺) and bromide ions (Br⁻) when molten.
2. Understand that during electrolysis, reduction occurs at the cathode. Reduction involves the gain of electrons.
3. Determine which ions will be reduced at the cathode. In this case, the calcium ions (Ca²⁺) will gain electrons.
4. Write the reduction half-equation for the reaction at the cathode: Ca²⁺ + 2e⁻ → Ca. This shows that calcium ions gain two electrons to form calcium metal.
5. Conclude that the substance produced at the cathode during the electrolysis of molten calcium bromide is calcium metal (Ca).