The gas phase reaction A$($g$)->2$B$($g$)$ occurs in a batch manner under a constant temperature of $27\backslash$deg C and a constant pressure of $1\mathrm{.}48$ atm.

occurs in the reactor. Initially, there are $8$ moles of A in the reactor. $80\%$ of A

the reaction time required to achieve the transformation,

a$)$ Assuming that there is no volume change in the reaction,

b$)$ When there is a volume change in the reaction,

Calculate.

$(-$rA$)=$ kA$.$CA

$2,$ kA$=0\mathrm{.}075$ L$/($mol$.$min$),$ R$=0\mathrm{.}082$ L$.$atm$/($mol$.$K$)$