Bond cleavage

BOND CLEAVAGE:
                           The breaking of bond is known as Bond cleavage.Breaking of bond means some bond are broken and some bond are formed.
                            Bond cleavage is of 2 types.i)Homolytic bond cleavage,ii)Heterolytic bond cleavage.
i) Homolytic bond cleavage:
                              Homo means equal.So Homolytic means species get equal ammount of electron.suppose one species is A and another is B.Both bonded with covalent bond,then the covelent bond 2e- get equally distributed to each species(Ae-,Be-).Homolytic bonf cleavage leads to formation of free radical.
Both get one e- by the breaking of covalent bond.

OCCURANCE OF HOMOLYTIC BOND CLEAVAGE:
           It predict the mechanism of a reaction by distributing/breaking of bond to represent the movement of electron.
       
CONDITION:
            a)presence of sunlight in the form of (UV-ultraviolet ray or energy of photon-plank's constant(h)*frequency).
            b)presence of peroxide.
   For example: H2O2(Hydrogen peroxide), Na2O2(sodium peroxide)
             C)High temperature.
             d)presence of Non-polar solvent(CCl4-carbon tetrachloride).

EXAMPLE:Chlorination of alkane->
ii) Heterolytic bond cleavage:
                           Hetero means different.It means the unequal division of two electron in different species(transfer of electron to only one species).Here one get both e-(electron) and other gets none.It leads to the formation of ion.
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NOTE: The both electorn in heretolytic bond cleavage is attracted towards that species which is more electronegative(EN).
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Here the arrow mark from A to B shows that the both the electron(e-) moves towards B.Because of  B is more electronegative  then A.In the breaking diagram of HCl Hydrogen(H+) carrying +ve charge(cation) and chlorine(cl-)carrying -ve charge(anion).
Electronegativity of cl- is more then electronegativity of H+.

         It is totally opposite to homolytic bond cleavage.most of the time.when bond is breaking into 2 part heterolytic breaking occur. 
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Summary:FUNDAMENTAL ABOUT GOC(General Organic Chemistry):->
1)How to break the bond, 2)which is more electronegative, 3)formation of free radical(Homolytic), 4)formation of ion(Heterolytic), 5)mechanism of reaction
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