Inductive effects are the effects of charge transmission by electrostatic induction through a chain of atoms in a molecule. The inductive effects is usually measured through the Hammett equation which describes the linear free-energy relationship of reaction rates and equilibrium constants. Fortunately, the scope covered in STPM Chemistry is not too large. You’ll learn all you need for your exams in this post, Part 3 of Berry Berry Easy notes on the Introduction to Organic Reactions for STPM Chemistry. Learn about the positive inductive effects and negative inductive effects in this post.
[Tips: Although not relevant to your studies at this point, to fully understand how inductive effects actually works, one must also understand a bit about the mesomeric effect. This is due to their combine effects to provide the net polar effect exerted by an atom (or groups of atoms) taking the place of a hydrogen atom on the parent chain of a hydrocarbon. Forget about this if it doesn't make sense, as this is considered to be difficult at this point.
It will also be helpful to look at the relative inductive effects to make sense of the tables shown below.]
STPM Chemistry Form 6 Note – Introduction of Organic Reaction (Part 3 – Final)
Crude Petroleum
Negative inductive effect (- I effect): electron-withdrawing group (electron acceptor)
| Functional group | Name |
| -NH2 | Amines |
| -Cl, -Br, -I | Halogens |
| -NO2 | Nitro group |
| -CN | Nitrile or cyanide group |
| -COOH | Carboxylic acid |
| -COOR | Ester |
| -C=O | Carbonyl groups in aldehydes and ketones |
| -SO3H | Sulphonic acid |
| -OH | Hydroxyl groups in alcohols and phenols |
| -OR | Ether |
| C6H5- | Phenyl group in aromatic compounds |
Positive inductive effect (+I effect): electron-donating group / electron-repelling group (electron donor)
| Functional group | Name |
| -CnH2n+1 | Alkyl group |
This ends the chapter on Introduction to Organic Reactions by Berry Berry Easy. Make sure you understand everything taught in the series of notes in this chapter before moving on to subsequent chapters in Organic Chemistry. Having a solid foundation is crucial to scoring in organic chemistry for Form 6 Chemistry in Malaysia. This is one of the best examination tips we can give for your STPM chemistry paper.
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