Electrolysis Process Overview

Study Notes

Electrolysis

A process using electric current to drive a non-spontaneous chemical reaction
Electrolytic cell is the setup for electrolysis, containing:
Electrodes
- Conductors immersed in the electrolyte
- Anode: Positively charged, oxidation (loss of electrons) occurs here
- Cathode: Negatively charged, reduction (gain of electrons) occurs here
Electrolyte
- Liquid or solution containing ions that conduct electricity
How electrolysis works:
- Direct current (DC) power source connected to electrodes creates an electric field
- Positive ions (cations) move towards the cathode, negative ions (anions) move towards the anode
- Redox reactions occur:
  - Anions lose electrons (oxidation) at the anode
  - Cations gain electrons (reduction) at the cathode

Examples of Electrolysis

Electrolysis of Water

Decomposes water into hydrogen and oxygen gas
Chemical equation: 2H₂O(l) → 2H₂(g) + O₂(g)
- Cathode: 2H₂O(l) + 2e⁻ → H₂(g) + 2OH⁻(aq)
- Anode: 4OH⁻(aq) → O₂(g) + 2H₂O(l) + 4e⁻

Electrolysis of Molten Sodium Chloride

Produces sodium metal and chlorine gas
Chemical equation: 2NaCl(l) → 2Na(l) + Cl₂(g)
- Cathode: Na⁺(l) + e⁻ → Na(l)
- Anode: 2Cl⁻(l) → Cl₂(g) + 2e⁻

Electroplating

Thin layer of one metal deposited onto another
Used for decorative purposes or corrosion prevention
- Example: Silver plating a steel spoon
  - Cathode: Ag⁺(aq) + e⁻ → Ag(s) – silver ions from solution are reduced and deposited
  - Anode: Ag(s) → Ag⁺(aq) + e⁻ – silver anode dissolves to replenish silver ions in the solution

Applications of Electrolysis

Production of metals, e.g., reactive metals like aluminum and sodium from their ores
Production of non-metals, e.g., chlorine and fluorine
Electroplating: coating objects with a thin layer of metal
Electrorefining: purifying metals like copper
Production of chemicals, e.g., sodium hydroxide
Battery recharging: reversing the chemical reactions in a rechargeable battery to restore its charge

Description

This quiz explores the fundamental concepts of electrolysis, including the roles of electrolytic cells, electrodes, and electrolytes. Understand the movement of ions and the redox reactions that occur during the process, as well as practical examples like the electrolysis of water. Test your knowledge on this essential electrochemical process!