What is the proper heating temperature for 100 mol/s feed A-B so that after passing through the pressure reducing valve 25% of the feed changes to vapor phase? It is known that the feed pressure is 12 atm with an A/B mole composition ratio of 3:2. The pressure after the valve is 1 atm. If the feed ratio suddenly changes to 4:1 what should be done to keep only 25% of the bait vaporized? (A : propanol, B: water)