Seawater containing $3\mathrm{.}5wt\%$ salt passes through a series of $5$ evaporators. Equal quantities of water are vaporized in each of the $5$ units. The water vapors are combined in a collection system and then condensed to obtain a product stream of fresh water. The brine leaving each evaporator is fed to the next evaporator except for the last evaporator. The brine leaving the fifth evaporator contains $7\mathrm{.}0wt\%$ salt.

$($a$)$ Draw and label,

$($i$)$ the process flow diagram completely.

$($ii$)$ the overall and individual unit boundaries.

$(5$ Marks$)$

$($b$)$ Perform the degree of freedom analysis for all the boundaries used to solve the question in $($c$).$

$(3$ Marks$)$

$($c$)$ Determine the fractional yield of fresh water from the process recovered $\frac{?}{kg{H}_{2}O}$ in process feed$)$ and the weight percent of salt in the solution leaving the third evaporator. $(12$ Marks$)$