$2.$ Calculate the plate height contributed by sorption$-$desorption mass transfer through a uniform liquid layer $($q$=2/3)$ of thickness $1$ micron coated on the inside of an open tubular capillary tube. The gas velocity is $10$ cm$/$sec$.$ The solute retention factor k$$ is $3\mathrm{.}0$ and the Ds value is $1$ x $10-5$ cm$2/$sec$.$ Be careful to use consistent units. Use equation Cs$=$ q$[($k$/(1+$k$)2]($df$)2()/$Ds$.$

Answer:$1\mathrm{.}24$ x $10-3$ cm