1. Mervin Lim
3B2(12)
CHEMISTRY ACE
OXIDATION AND REDUCTION
REDOX

2. What is a redox?
A redox is concerned with net electron flow to
and from a defined centre during a chemical
reaction.

3. Defined Centres
 Atom
 Atomic ion
 Molecule
 Molecular ion
 Multifunctional molecule

4. What is a redox?
Redox
Reduction Oxidation

5. Aspects
Redox
Oxidation Reduction
Oxidizing Agent Reducing Agent
Lose electrons Gain electrons

6. How to memorise?
“LEO says GER”
Lose Electrons is Oxidation
Gain Electrons is Reduction

7. Sum up
1. Oxidation  loss of electrons
2. Reduction  gain of electrons
3. Oxidizing agent  Gains electrons during
reaction and therefore reduced reaction
4. Reducing agent  Loses electrons during
reaction and is therefore oxidized during
reaction
5. Oxidized form  Form of molecule lacking
electrons
6. Reduced form  Form of molecule having
electrons

8. How can oxidation of a defined centre be
changed?
1) Single Electron Transfer (SET)
-To the defined centre (reduction) or from the
defined centre (oxidation)
E.g. Iron

9. How can oxidation of a defined centre be
changed?
2) Reversal of bond polarization at defined
centres
E.g. Carbon

10. 3 Types of Redox Reaction
1st :
Gain of electrons is reduction,
Loss of electrons is oxidation

11. 3 Types of Redox Reaction
2nd :
Gain of hydrogen* is reduction,
Loss of hydrogen* is oxidation
*or other electro positive element

12. 3 Types of Redox Reaction
2nd :
Gain of hydrogen* is reduction,
Loss of hydrogen* is oxidation
*or other electro positive element

13. 3 Types of Redox Reaction
3rd :
Loss of oxygen* is reduction,
Gain of oxygen* is oxidation
*or other electro positive element

14. Classification of Redox
Types
 Single Electron Transfer Electron Donor
Agent
 Hydride Complex Agent
 Lewis Acid Hydride Donor Agent
 Hydrogen Agent
 Dissolved Metal Agent
 Miscellaneous Agent

15. That is all
Thank you