b$)$ Adsorption of $N_2$ on $Ti{O}_2$ was carried out at $75K.$ A plot of $\frac{Z}{1-Z}V$ versus $)=(\frac{P}{P}$ gives a straight line with an intereept $4{10}^{-6}m{m}^{-3}$ and slope $1{10}^{-3}m{m}^{-3}.$ Find out volume $($in $($:$m{m}^3\}$ corresponding to the monolayer coverage.

c$)$ Find the surface area occupied by a single molecule of a fatty acid at $300K.$ Assuming that fatty acid molecules are oriented vertically and they form a surface film of one molecule thickness. Given $a=0\mathrm{.}179,{}_0=72\mathrm{.}5dy\frac{n}{c}m.$