What is the balanced half-reaction for the oxidation occurring at the anode in the galvanic cell: Co(s) | Co2+(aq) || Cu2+(aq) | Cu(s) in an acidic solution?

• A. Cu2+(aq) + 2e- → Cu(s)
• B. Co2+(aq) + 2e- → Co(s)
• C. Cu(s) → Cu2+(aq) + 2e-
• D. Co(s) → Co2+(aq) + 2e-

Answer: (D)

Verified step by step guidance

1. Identify the components of the galvanic cell: Co(s) | Co2+(aq) || Cu2+(aq) | Cu(s). The cell consists of cobalt and copper electrodes with their respective ions in solution.
2. Understand that oxidation occurs at the anode. In a galvanic cell, the anode is where oxidation takes place, meaning the loss of electrons.
3. Determine which species is oxidized. In this cell, cobalt (Co) is oxidized to cobalt ions (Co2+), losing electrons in the process.
4. Write the oxidation half-reaction for cobalt. The oxidation half-reaction involves the conversion of solid cobalt to cobalt ions, releasing electrons: ${\mathrm{Co}}_{\left(s\right)}\to {\mathrm{Co}}_{({\mathrm{aq}}^{\mathrm{2+}}}+2e-$
5. Ensure the half-reaction is balanced. Check that the number of atoms and charges are balanced on both sides of the equation. In this case, cobalt is balanced with two electrons released during oxidation.