Q4. It is required to strip 90% of the ammonia (NH3) from aqueous ammonia solution of 15 mol% in a countercurrent tray tower. The NH3-free dry air input is 15 kmol/h and aqueous ammonia solution enters the tower at a rate of 10 kmol/h. The tower operates at 300 K and 1 atm. The equilibrium relation is x = 1.83 y. (a) Write suitable balance equation to find ammonia composition in exit gas mixture. (b) Determine the number of ideal trays necessary for this separation. Use graphical method or Kremser analytical method. (4 + 6 = 10 M)