We are separating 250 kg moles/hr of a methanol-water mixture in a distillation column that has a total condenser and a partial reboiler. The feed composition is 0.3 mole fractional methanol, and the feed is a subcooled liquid. Three moles of feed will con-dense 1 mole of vapor in the column. Distillate is a saturated liquid with a concentration of 0.90. Bottoms concentration is 0.02. Constant molal overflow can be assumed. a. Find the minimum external reflux ratio for this separation. b. Find the minimum number of stages needed for separation (this is total reflux). c. If we use L/D