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    The current theory i have is that sn2 occurs in primary because the c-x (where x is the halogen) bond is too strong to break on its own. In tertiary halogenoalkane, the alkyl groups act as electron pushing groups which makes the carbon in c-x less positively polarised and so weakens the c-x bond - this allows sn1 mechanism and the c-x bond can break without OH- attacking it and sn2 cannot take place due to alkyl groups leaving no space for the attack. Is this theory correct? In an a2 exam is this explanation acceptable?


    Also what mechanism occurs for secondary halogenoalkanes? I think i heard somewhere both sn1 and sn2 occurs not sure though. If they both occur i would guess both occur in equal ratio?
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    (Original post by thebrahmabull)
    The current theory i have is that sn2 occurs in primary because the c-x (where x is the halogen) bond is too strong to break on its own. In tertiary halogenoalkane, the alkyl groups act as electron pushing groups which makes the carbon in c-x less positively polarised and so weakens the c-x bond - this allows sn1 mechanism and the c-x bond can break without OH- attacking it and sn2 cannot take place due to alkyl groups leaving no space for the attack. Is this theory correct? In an a2 exam is this explanation acceptable?


    Also what mechanism occurs for secondary halogenoalkanes? I think i heard somewhere both sn1 and sn2 occurs not sure though. If they both occur i would guess both occur in equal ratio?
    Check this interactive on nucleophilic substitution
 
 
 
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