Electrolysis & Redox Flashcards

All 4 cards in this deck

In electrolysis, what happens at the cathode in terms of electrons?

Positive ions gain electrons, so reduction occurs at the cathode.

In electrolysis, what happens at the anode in terms of electrons?

Negative ions lose electrons, so oxidation occurs at the anode.

What are the steps to write a half equation for a reaction at the cathode?
e.g. hydrogen ions forming hydrogen gas, $H_2$

1. Write the ions on the left and the product on the right: $2H^+ \rightarrow H_2$
2. Add electrons to the left-hand side to balance the charges: $2H^+ + 2e^- \rightarrow H_2$

What is the balanced half equation for the formation of oxygen from hydroxide ions at the positive electrode?

$4OH^- \rightarrow O_2 + 2H_2O + 4e^-$