$\underset{\mathbf{\left(}\mathbf{\text{ monochlorination }}\mathbf{\right)}}{\overset{{\mathrm{Cl}}_2:\mathrm{hv}}{\to }}\mathrm{N}$,isomeric products $\left({\mathrm{C}}_5{\mathrm{H}}_{11}\mathrm{Cl}\right)$isomeric products

  $N \left({\mathrm{C}}_5{\mathrm{H}}_{11}\mathrm{Cl}\right)\stackrel{ \mathrm{Fractional}distillation}{\to }\mathrm{M}$(isomeric products) , N & M respectively is