Vinyl chloride monomer $($VCM$),$ which is used to manufacture PVC$,$ can be produced from acetylene and hydrogen chloride via the following reaction:

C$2$H$2+$ HCl $$ C$2$H$3$Cl

acetylene hydrogen chloride vinyl chloride

A side reaction also occurs, producing dichloroethane $($DCE$)$ as an undesired by$-$product:

C$2$H$3$Cl $+$ HCl $$ C$2$H$4$Cl$2$

vinyl chloride hydrogen chloride dichloroethane

$1\mathrm{.}1$ With reference to specific components in the system, recommend a scheme to minimise the undesired product $($DCE$).$ Justify your recommendation. $(3)$

$1\mathrm{.}2$ Draw up a table of the molecular weights and boiling points $($in $$C$)$ of the components in the system. List the boiling points from lowest to highest. $(4)$

$1\mathrm{.}3$ Based on your answers in $1\mathrm{.}1$ and $1\mathrm{.}2,$ develop a preliminary process flow diagram $($PFD$)$ for the system. Provide your reasoning. $(6)$

$1\mathrm{.}4$ Plot a graph of the economic potential versus the selectivity. $(10)$

Component Value $($$$/$kg$)$

Hydrogen chloride $0\mathrm{.}35$

Acetylene $0\mathrm{.}8$

Vinyl chloride $0\mathrm{.}85$

Dichloroethane $0$

$[23]$

Definition of Selectivity: $=$

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