We are required to reduce the DMF content of the raw feed from 55 mol%(balance is nitrogen). A separator is designed to remove exactly two-thirds of theDimethyl Formamide (DMF) fed to it. The extract will contain DMF in a pure form.(a) (10 points) Draw a PFD for the above and perform a degree of freedom analysis.(b) (8 points) Solve for the exit stream composition. Did you choose a basis

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

i think it's letter a.