Short Answer Type
Long Answer TypePredict the order of reactivity of the following compounds in SN1 and SN2 reactions:
(a) The four isomeric bromobutanes.
(b) C6H5 H2Br, C6H5CH (C6H5Br, C6H5CH (CH3)Br, C6H5C(CH3)(C6H5)Br.
Short Answer TypeWhy (-NO2) group shows its effect only at ortho- and para-position and not at meta–position?
Long Answer TypeShort Answer TypeExplain the reason:
The reactivity order of alkyl bromides is tert alkyl bromide > sec alkyl bromide > primary alkyl bromide.
i) The given order is follow the SN1 mechanism. In which carbon halogen bond is break and form carbocation and halogen ion.
ii) The carbocation is formed is then attacked by nucleophile in step to complete the substitution reaction.
According to SN1 mechanism more is stability of carbocation easy is formation of compound. Hence the order of alkyl bromides are given as;
30 > 20 > 10
Since tertiary cation is more stable than secondary and secondary is more stable than primary.
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