$2.$ A feed of $1200$ kg aqueous solution of pyridine per hour $(50\%$ by mass$)$ is to be extracted with pure benzene to reduce the solute content in the raffinate to $3\%.$ Determine the minimum solvent rate. Determine the number of ideal stages required if the solvent rate is $1\mathrm{.}2$ times the minimum

Water layer Benzene layer

Pyridine $($mass $\%)$ Benzene $($mass $\%)$ Pyridine $($mass $\%)$ Benzene $($mass $\%)$

$1\mathrm{.}1703\mathrm{.}2894\mathrm{.}54$

$3\mathrm{.}5509\mathrm{.}7587\mathrm{.}46$

$7\mathrm{.}39018\mathrm{.}3579\mathrm{.}49$

$13\mathrm{.}460\mathrm{.}1526\mathrm{.}9971\mathrm{.}31$

$22\mathrm{.}780\mathrm{.}2531\mathrm{.}4266\mathrm{.}46$

$32\mathrm{.}150\mathrm{.}4434\mathrm{.}3264\mathrm{.}48$

$42\mathrm{.}472\mathrm{.}3836\mathrm{.}8559\mathrm{.}35$

$48\mathrm{.}873\mathrm{.}9939\mathrm{.}4556\mathrm{.}43$

$49\mathrm{.}824\mathrm{.}2839\mathrm{.}2755\mathrm{.}72$

$56\mathrm{.}0519\mathrm{.}5648\mathrm{.}3940\mathrm{.}05$