What is the correct order of reaction types in the following sequence?

${\mathrm{C}}_3{\mathrm{H}}_7\mathrm{Br}\stackrel{\mathrm{I}}{\to }{\mathrm{C}}_3{\mathrm{H}}_7\mathrm{OH}\stackrel{\mathrm{II}}{\to }{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{COOH}\stackrel{\mathrm{III}}{\to }{\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{COOC}}_2{\mathrm{H}}_5$

Which process can produce a polyester?

Which statements about substitution reactions are correct?

I. The reaction between sodium hydroxide and 1-chloropentane predominantly follows an ${\mathrm{S}}_{\mathrm{N}}2$ mechanism.

II. The reaction between sodium hydroxide and 2-chloro-2-methylbutane predominantly follows an ${\mathrm{S}}_{\mathrm{N}}2$ mechanism.

III. The reaction of sodium hydroxide with 1-chloropentane occurs at a slower rate than with 1-bromopentane.

Which two molecules in given figure are cis–trans isomers of each other?