A water-isopropanol mixture at its bubble point containing \(10 \mathrm{~mol} \%\) isopropanol is to be continuously rectified at atmospheric pressure to produce a distillate containing \(67.5 \mathrm{~mol} \%\) isopropanol. Eighty-five percent of the isopropanol in the feed must be recovered. VLE data are given in Problem 6.13. If a reflux ratio of 1.5 times the minimum is used, how many theoretical stages will be required:

(a) If a partial reboiler is used?

(b) If no reboiler is used and saturated steam at \(101.3 \mathrm{kPa}\) is introduced below the bottom plate?