Deduce a two-step reaction pathway which can be used to convert 1-bromopropane into butanoic acid. Draw the structural formula of the organic product formed for each step and identify the reagents involved.

Deduce a two-step reaction pathway which can be used to convert propan-2-ol into 1,2-dibromopropane. Draw the structural formula of the organic product formed for each step and identify the reagents involved.

(addition of) Mg/magnesium;

\({\text{C}}{{\text{H}}_3}{\text{C}}{{\text{H}}_2}{\text{C}}{{\text{H}}_2}{\text{MgBr}}\);

(addition of) \({\text{C}}{{\text{O}}_2}\) /carbon dioxide and \({{\text{H}}_2}{\text{O}}\)/water;

\({\text{C}}{{\text{H}}_3}{\text{C}}{{\text{H}}_2}{\text{C}}{{\text{H}}_2}{\text{C}}{{\text{O}}_2}{\text{H}}\) / \({\text{C}}{{\text{H}}_3}{\text{C}}{{\text{H}}_2}{\text{C}}{{\text{H}}_2}{\text{COOH}}\);

concentrated phosphoric acid/\({{\text{H}}_3}{\text{P}}{{\text{O}}_4}\)/sulfuric acid/\({{\text{H}}_2}{\text{S}}{{\text{O}}_4}\);

\({\text{(C}}{{\text{H}}_{\text{3}}}{\text{)CH=C}}{{\text{H}}_{\text{2}}}\);

\({\text{B}}{{\text{r}}_2}\)/bromine;

\({\text{BrC}}{{\text{H}}_2}{\text{CHBrC}}{{\text{H}}_3}\);

About half of the candidates struggled with part (a), with only the best candidates scoring the marks, which demonstrated that the candidates found reaction pathways difficult.

Part (b) was answered better than part (a), but quite a few candidates did not state concentrated.