Note : Attempt all questions. 1. 8000lb/h of a 5% by weight solution of acetaldehyde in toluene is to be treated with 5000 lbs/h of water in a 6 stage extraction column operating under counter flow condition. If the concentration of feed is suddenly changed to 3% by weight solution, how long will it take for the extractor to settle down to steady state operation under the new conditions? Data: Equilibrium relation is Y=2.2X,Y=lb of acetaldehyde/lb of water, X=lb of acetaldehyde/lb of toluene. Hold-up per stage is constant at: 750lb Toluene and 300lb of water