⚛️ Redox Reactions — Oxidation, Reduction & Electrochemistry

Redox reactions are more than just electron transfers—they power batteries, biology, and DAT questions.
Expect problems involving oxidation numbers, reaction balancing, and cell diagram interpretation.
This guide will help you simplify the redox rules and crush electrochemistry questions with confidence.

⚛️ Redox Reactions — Oxidation, Reduction & Electrochemistry

🔋 What Are Redox Reactions?

Redox = Reduction + Oxidation

  • Oxidation: Loss of electrons

  • Reduction: Gain of electrons
    📌 DAT Memory Trick: OIL RIG (Oxidation Is Loss, Reduction Is Gain)

🧮 Assigning Oxidation Numbers

Rule Example
Element alone = 0 O₂, Fe, Cl₂
Group 1/2 metals = +1 / +2 Na⁺, Ca²⁺
Oxygen = –2 (peroxides = –1) H₂O (–2), H₂O₂ (–1)
Hydrogen = +1 (–1 w/ metals) HCl (+1), LiH (–1)
Halogens = –1 (except w/ O) NaCl (–1), ClO₄⁻

⚖️ How to Balance Redox Reactions (Acidic Solution)

  1. Balance all elements except O and H

  2. Balance O using H₂O

  3. Balance H using H⁺

  4. Balance charges with e⁻

  5. Combine half-reactions and cancel species

✅ For basic solutions, add OH⁻ to both sides to neutralize extra H⁺.

⚡ Galvanic vs. Electrolytic Cells

Feature Galvanic Cell Electrolytic Cell
Spontaneous? Yes (ΔG < 0) No (ΔG > 0)
Energy Source Generates current Requires external power
Anode Oxidation (–) Oxidation (+)
Cathode Reduction (+) Reduction (–)
Electron Flow Anode → Cathode Anode → Cathode
Example Batteries Electroplating

📌 DAT Tip: AnOx & RedCat = Anode Oxidation, Cathode Reduction

🧠 Redox DAT Question Types

  • “Assign oxidation numbers to each atom”

  • “Balance this redox reaction in acid/base”

  • “Which species is reduced?”

  • “What’s the function of the salt bridge?”

  • “What is the direction of electron flow?”

🎯 Call to Action

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✅ Summary

  • Redox = oxidation + reduction; track electrons

  • Assign oxidation numbers based on key rules

  • Use half-reactions to balance redox in acidic/basic media

  • Understand how electrochemical cells function and label components



 

Frequently Asked Questions (FAQs)

  • Aim for 4-6 focused hours, ensuring you incorporate breaks to avoid burnout.

  • Practice mindfulness techniques, take practice exams under realistic conditions, and maintain a balanced lifestyle.

  • Set short-term goals, seek support from mentors, and reward yourself for small achievements.

  • Regular exercise improves focus, reduces stress, and enhances overall mental clarity.

  • KOTC offers personalized learning tools, gamification features, and adaptive question banks to help students stay on track without burnout.

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