You are tasked to design a new PFR to produce a new semiconductor additive, known as Chemical B$,$ developed by your company. The gas phase second order reaction involved in the process is as shown below. TABLE Q$2$ listed the parameter values involved.

$A2B+C$

TABLE Q$2$: Parameter Values for Chemical B Production

$\backslash$table$[[$Parameter$,$Values$],[k(\frac{m^3}{m}ol*s),1],[C_{10}(\frac{\text{m}\text{o}\text{l}}{m^3}),0\mathrm{.}5],[v_0(\frac{m^3}{s}),2],[A_c(m^2),5],[\backslash$table$[[$Number of tubes$],[$involved$]],1]]$

a$.$ Describe the effect of expansion factor, $,$ towards reaction conversion.

$[5$ marks$]$

b$.$ Calculate the length of the PFR to achieve $70\%$ of reactant conversion if;

i$.$ Volume change is neglected.

$[7$ marks$]$

ii$.$ Volume change is considered.

$[13$ marks$]$