Question
Explain reactivity order towards $SN^2$ reaction of alkyl halides.
✓
Answer
$\rightarrow$ Reactivity order of primary secondary and tertiary halides toward $SN^2$ reaction is $CH_3-X > 1^\circ -$ halide $> 2^\circ -$ halide $> 3^\circ -$ halide.
$\rightarrow$ The presence of bulky substituents on or near the carbon atom have a dramatic inhibiting effect.
$\rightarrow$ Of the simple alkyl halides, methyl halides react most rapidly in $SN^2$ reactions because there are only three small hydrogen atoms.
$\rightarrow$ Tertiary halides are the least reactive because bulky groups hinder the approach nucleophiles.
$\rightarrow$ Thus, the order of reactivity followed is: Primary halide $>$ Secondary halide $>$ Tertiary halide.
$\rightarrow$ The presence of bulky substituents on or near the carbon atom have a dramatic inhibiting effect.
$\rightarrow$ Of the simple alkyl halides, methyl halides react most rapidly in $SN^2$ reactions because there are only three small hydrogen atoms.
$\rightarrow$ Tertiary halides are the least reactive because bulky groups hinder the approach nucleophiles.
$\rightarrow$ Thus, the order of reactivity followed is: Primary halide $>$ Secondary halide $>$ Tertiary halide.
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