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      - The C-Cl bond in the halogenoalkane starts to lengthen and weaken
 
      - The chloride ion is eventually detached from the carbon atom and a flat carbocation
        forms. This is the rate determining step.
 
      - The hydroxide ion could attack from the left-hand side, leading to inversion of the
        configuration of the carbon skeleton; or
 
      - attack could come from the right, leading to retention of configuration.
 
      - The use of a chiral halogenoalkane in this reaction leads to  production of a
        racemic mixture if the amount of attack from each side is equal. The hindrance caused by
        the departing cloride ion gives about 40% attack from the right and 60% from the left,
        however.
 
     
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