Question

What is the reason for these compounds to undergo Sn1 or Sn2 or both mechanisms?

1-chloropropanone(chloroacetone)
benzyl chloride
bromobenzene
bromocyclopentane
bromocyclohexane
2-bromobutane
2-chlorobutane
1-chlorobutane
2-chloro-2-methylpropane

Answer 1

Let's look at the laundry list you've collected in a better format,

Every substrate you listed could generally undergoes a bimolecular nucleophilic substitution reaction, except `(3)`.

Moreover, the primary alkyl halides would undergo SN2, the secondary alkyl halides could undergo either SN1 or SN2 (esp. dependent on the other conditions), and the tertiary alkyl halide `(8)` could only undergo SN1.