The number of actual trays required for steam$-$stripping an acetone$-$rich liquor containing $0\mathrm{.}573$ mole percent acetone in water is to be estimated. The design overhead recovery of acetone is $99\mathrm{.}9$ percent, leaving $18\mathrm{.}5$ pm weight of acetone in the stripper bottoms. The design operating temperature and pressure are $101\mathrm{.}3$ kPa and$94\backslash$deg C respectively, the average liquid$-$phase viscosity is $0\mathrm{.}30$ cP$,$ and the average value of K$=$ y$\backslash$deg $/$x for these conditions is $33.$ By choosing a value of mGMILM $=$ S $=4-1=1\mathrm{.}4$ and noting that the stripping medium is pure steam $($i$.$e$.,*\backslash$deg $]=0),$ the number of theoretical trays according to the graph provided