Arrange the following alkyl bromides in order from most reactive to least reactive in an SN₂ reaction: 1-bromo-2-methylbutane, 1-bromo-3-methylbutane, 2-bromo-2-methylbutane, and 1-bromopentane.

1 - bromopentane 1 - bromo-3-methylbutane 1-bromo2-methylbutane 2-bromo-2-methylbutane

Explanation:

SN square reaction is a concentrated reaction. All the bond making and bond braking occur in one step

The nucleophile attack the back side of the carbon that bears the halide and replace it