Question

Define Anti Markovnikov's Rule And Markovnikov's with example.

Answer 1

Markovnikov's Rule:

• According to this rule, in an unsymmetrical alkene when the addition of halogen acid (HX) takes place, then the negative part of the halogen acid is attached to that carbon atom which is double bonded as well have the least number of hydrogen atoms.

For example: The addition of hydrogen bromide to propene.

$\underset{\mathrm{Propene}}{{\mathrm{CH}}_3-\mathrm{CH}={\mathrm{CH}}_2}+\underset{\mathrm{Hydrogen}\mathrm{bromide}}{\mathrm{H}-\mathrm{Br}}\to \underset{2-\mathrm{Bromo}\mathrm{propane}}{{\mathrm{CH}}_3–\mathrm{CHBr}-{\mathrm{CH}}_3}$

In this reaction, bromine is a negative part of halogen acid which attaches to the double-bonded carbon atom and has the least number of the hydrogen atom.

Anti- Markovnikov's Rule:

• Anti- Markovnikov Rule is also called the peroxide effect and the kharasch effect.
• According to this rule, in an unsymmetrical alkene when the addition of halogen acid (HX) takes place, then the negative part of the halogen acid is attached to that carbon atom which is double bonded as well have the more hydrogen atoms.

For example: The addition of hydrogen bromide to propene in presence of peroxide.

$\underset{\mathrm{Propene}}{{\mathrm{CH}}_3-\mathrm{CH}={\mathrm{CH}}_2}+\underset{\mathrm{Hydrogen}\mathrm{bromide}}{\mathrm{H}-\mathrm{Br}}\stackrel{\mathrm{Peroxide}}{\to }\underset{1-\mathrm{Bromo}\mathrm{propane}}{{\mathrm{CH}}_3-{\mathrm{CH}}_2-{\mathrm{CH}}_2-\mathrm{Br}}$