Course Content
Module 1: Introduction to Electrochemistry
Overview of electrochemistry, its applications, and relevance in daily life and industrial processes.
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Definition and Importance of Electrochemistry
Module 2: Redox Reactions
Understanding oxidation, reduction, oxidation numbers, and balancing redox equations.
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Oxidation and Reduction Concepts
Oxidation Numbers
Balancing Redox Equations
📘 Module 3: Electrolysis
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Introduction to Electrolysis
Faraday’s Laws of Electrolysis
Industrial Applications of Electrolysis
Electrolysis Calculations
📘 Module 4: Redox Titrations
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Introduction and Indicators
KMnO₄ and Fe²⁺ Titration – Theory and Procedure
Oxalic Acid vs KMnO₄ Titration – Theory and Procedure
Iodometric Titrations – Iodine vs Thiosulfate (S₂O₃²⁻)
Electrode Potentials
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Standard Electrode Potentials (E° Values)
Electrochemical Cells and E° Cell Calculations
The Nernst Equation – Effect of Concentration on E°cell
📘 Module 6: Corrosion
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🧪 Lesson 1: Causes, Mechanism, and Prevention of Corrosion
📘 Module 7: Conductivity of Electrolyte Solutions
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🧪 Lesson 1: Electrical Conductivity and Factors Affecting It
📘 Module 8: Electrolytic Cells
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🧪 Lesson 1: Electrolysis Mechanism and Product Prediction
🧪 Lesson 2: Electrolysis of Water and Brine
📘 Module 9: Applications of Electrolysis in Industry
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🧪 Lesson 1: Electrolysis in Metal Extraction, Refining, and Electroplating
📘 Module 10: Redox Titrations and Calculations
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🧪 Lesson 1: Introduction, Procedure, and Redox Calculations
Advanced Chemistry: Electrochemistry

Introduction
An electrolytic cell uses electrical energy to drive a non-spontaneous redox reaction. This is the reverse of a galvanic cell. The process is called electrolysis, and it is widely used in industries such as electroplating, metal extraction, and water purification.

🔹 1. What is Electrolysis?

Electrolysis is the chemical decomposition of an electrolyte by the passage of an electric current.

  • Requires DC power supply

  • Involves two electrodes (anode and cathode)

  • Electrolyte must contain mobile ions

🔹 2. Key Components of Electrolytic Cell

Component Role
Power Source Provides external energy (DC)
Anode (+ve) Site of oxidation (loss of electrons)
Cathode (–ve) Site of reduction (gain of electrons)
Electrolyte Ionic solution that conducts current

📌 Mnemonic: An Ox, Red Cat

  • ANode = OXidation

  • REDuction = CAThode

🔹 3. Half-Reactions at Electrodes

General format:

  • At Cathode (reduction):
    Positive ions gain electrons

     
    M⁺ + e⁻ → M

  • At Anode (oxidation):
    Negative ions lose electrons

     
    X⁻ → X + e⁻

🧪 Example 1: Electrolysis of Molten NaCl

Electrolyte: NaCl(l)

At cathode:

scss
Na⁺ + e⁻ → Na(l)

At anode:

scss
2Cl⁻ → Cl₂(g) + 2e⁻

✅ Products: Sodium metal (cathode), chlorine gas (anode)

🧪 Example 2: Electrolysis of Aqueous CuSO₄ with Copper Electrodes

At cathode:

scss
Cu²⁺ + 2e⁻ → Cu (deposited)

At anode:

scss
Cu → Cu²⁺ + 2e⁻ (dissolves)

✅ Result: No net change in Cu²⁺ concentration; used in electroplating

🔹 4. Factors Determining Electrolysis Products

Factor Effect
Nature of electrolyte Determines available ions
Electrode type Inert (e.g., Pt) or reactive (e.g., Cu)
Ion discharge preference Based on E° values, especially in water
Concentration of ions Higher concentration may affect preference

🔹 5. Preferential Discharge Rules (Water Electrolysis)

At cathode (cations compete):

  • H⁺ is discharged unless metal ion is below H⁺ in reactivity series
    (e.g., Cu²⁺ is discharged over H⁺)

At anode (anions compete):

  • OH⁻ is discharged unless halide ions (Cl⁻, Br⁻, I⁻) are present in high concentration

🔹 6. Real-World Applications of Electrolysis

  • Electroplating metals (e.g., silver, chromium)

  • Extraction of metals (e.g., aluminium from bauxite)

  • Chloralkali process (producing NaOH, Cl₂, and H₂)

  • Electrorefining impure metals (e.g., copper)

🧠 NECTA Tips

  • Always state electrode reactions separately

  • Identify whether electrodes are inert or reactive

  • Use correct phase symbols (g, l, s, aq)

  • Label products clearly in diagrams

  • Be ready to justify which ion is discharged and why

✅ Summary

  • Electrolytic cells use electricity to drive non-spontaneous reactions

  • Oxidation at anode, reduction at cathode

  • Products depend on electrolyte, ion reactivity, and electrodes

  • Industrially used for plating, purification, and metal extraction

  • Common in NECTA theory and practicals

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