Question

why is there a difference in reactivity of 1-bromobutane, 2-bromobutane, and 2-bromo-2-methylpropane?

Answer 1

generally alkyhalides undergo nucleophilic or elimination reactions

for SN1 or E1 substrate should be able to form stable carbocation that can undergo easily

so order will be

2-bromo-2-methylpropane > 2-bromobutane > 1-bromobutane

where as in case of SN2or E2 reaction

the carbon which is attached to halogen must be less substituted

then only nucleophile can come attack quickly if more and more substitution steric bulkyness is more rate of the reaction will be less

then order will be 1-bromobutane > 2-bromobutane > 2-bromo-2-methylpropane