Aliquid-process feed stream f contains 99 mol-% of species 1 and 1 mol-% of impurity, species 2. the impurity level is to be reduced to 0.1 mol-% by contacting the feed stream with a stream s of pure liquid solvent, species 3, in a mixer/settler. species 1 and 3 are essentially immiscible. owing to "good chemistry," it is expected that species 2 will selectively concentrate in the solvent phase. (a) with the equations given below, determins the required solvent-to-feed ratio ns/nf (b) what is mole fraction x2 of impurity in the solvent phase leaving the mixer/settler? (c) what is "good" about the chemistry here? with respect to liquid-phase non-idealities, what would be "bad" chemistry for the proposed operation? given: ge12/rt = 1.5 x1x2 ge23/rt = - 0.8x2x3