Organic Chemistry Reaction Mechanisms

## Inductive Effect

It is a permanent effect , in which an electronegative or electropositive group attached to a carbon chain , tries to pull or push the electron towards itself. If the Electronegative Group pulls electron density towards itself it is called - I effect . If the Electropositive Group pushes the electron density towards the Carbon chain , it is called as + I effect . The pulling or pushing process develops a "**slight"**  positive or negative charge .

Remember : Electronegative Group : - I effect

Electropositive Group :- + I effect

## Hyperconjugation Effect

The higher the degree of Carbon atom ; the more is the hyerconjugation ffect .

## Nucleophilicity

**Hard Nucleophiles** are highly unstable and reactive . e.g. Hydrogen (-1 charge ; low atomic size)

**Soft Nucleophiles**  are less unstable and less reactive . e.g. Chlorine (-1 charge ; large atomic size)

The nucleophilicity is decided by its electron charge density .

## SN1 Reactions

Basic Understanding : Reaction takes place in two steps : 1) breaking of bond 2) Making of bond . The slowest step among the two is the Rate Determining Step .

The process of solvation releases energy for breaking the bond . The nucleophile will pull the electron density from Carbon and acquire -1 charge . Carbon acquires +1 charge . The cleavage of bond happens only in presence of energy . The formation of Carbocation is exothermic in nature . Therefore , there is rise in energy to break the bond , then there is drop in energy as the process is exothermic .

When the bond is broken in the first step , energy is gained , this energy is then liberated to form a bond with the attacking reagent . When the leaving group leaves , carbocation is formed ; thus we have the order of stability :-

Stability : Reaction favored by stable reagents .

CH3 < 1o < 2o < 3o

## SN2 Reactions

Basic Understanding : Reaction takes place in one step : 1) Breaking and making of bond takes place simultaneously . It is the only Rate determining step . The reagent attacks the anti-bonding Molecular orbital of the less stable atom and the electron density starts shifting towards it ; which results in breaking of the old bond . The Nucleophilicity of the attacking reagent and nature of the removed group determine the rate of the reaction .

The attacking reagent should be more unstable , so that it attacks easily ; and the leaving group should be more stable , so that it leaves easily .

The process of particles of a solvent surrounding the solute is called as Solvation . If the reaction is taking place in a solution , then the nature of the solvent also decides the rate of reaction . When a nucleophile is present in a solvent , the solvent particles surround it . The solvent particles form thick layers if the solvent is more polar . Thus , the nucleophile finds it more difficult to donate its electron to another empty orbital . Thus , more the polarity of solvent , lesser will be the rate of reaction .

The attacking reagent will attack the unstable group , while the stable group will leave the parent compound .

Stability : Reaction is favored by unstable reagents . ... The reagent cannot attack from both the sides.

CH3 >1o > 2o > 3o

Single Bond > Double Bond > Triple Bond (Due to electron cloud density)

Open Chain > Closed Chain > Benzene

## Organic Tests

1) Peroxide Test : Use Fe2+ and KCNS

Also you can use KI and Starch to detect formation of ether peroxide .

## Catalysts and Conditions

1. **Reduction**
	* sffs
	* sdas
	* ad
2. **Oxidation**
3. **Hydrolysis**