Anode and Cathode Reactions in Electrolysis

Study Notes

Oxidation reaction: occurs at the anode (negative electrode), where electrons are lost
- Example: Zn (s) → Zn²⁺ (aq) + 2e⁻
Reduction reaction: occurs at the cathode (positive electrode), where electrons are gained
- Example: Cu²⁺ (aq) + 2e⁻ → Cu (s)
Net reaction: combination of oxidation and reduction reactions, resulting in the transfer of electrons from anode to cathode
- Example: Zn (s) + Cu²⁺ (aq) → Zn²⁺ (aq) + Cu (s)

Electrolytes:
- Substances that facilitate the flow of ions between electrodes
- Can be solid, liquid, or gaseous
- Examples: saltwater, hydrochloric acid, potassium nitrate
Electrode materials:
- Determine the efficiency and selectivity of the electrochemical reaction
- Examples:
  - Inert electrodes: platinum, gold, graphite
  - Reactive electrodes: zinc, copper, iron

Electromotive force (EMF): the potential difference between the anode and cathode, measured in volts (V)
- Represents the maximum potential of a cell to drive an electric current
Cell voltage: the actual voltage of an electrochemical cell, affected by factors such as concentration, temperature, and electrode materials
Standard electrode potential: the potential of an electrode in a standard state, used to calculate the EMF of a cell
- Measured in volts (V), relative to the standard hydrogen electrode (SHE)

Oxidation reaction occurs at the anode (negative electrode), where electrons are lost, resulting in the formation of ions.
Reduction reaction occurs at the cathode (positive electrode), where electrons are gained, resulting in the formation of atoms.
Net reaction is the combination of oxidation and reduction reactions, resulting in the transfer of electrons from anode to cathode.

Facilitate the flow of ions between electrodes, enabling the electrochemical reaction to occur.
Can exist in solid, liquid, or gaseous states.
Examples: saltwater, hydrochloric acid, potassium nitrate.

Determine the efficiency and selectivity of the electrochemical reaction.
Inert electrodes: platinum, gold, graphite, which do not participate in the reaction.
Reactive electrodes: zinc, copper, iron, which participate in the reaction.

The actual voltage of an electrochemical cell, affected by factors such as concentration, temperature, and electrode materials.

The potential of an electrode in a standard state, used to calculate the EMF of a cell.
Measured in volts (V), relative to the standard hydrogen electrode (SHE).