[Elliania]

The following link is to a problem presented to me the other day in my Inorganic II class.  Problem 7, part D is the part that I am having issues with. 

http://ocw.mit.edu/NR/rdonlyres/Chemistry/5-44Fall-2004/BA97FF8D-A1FF-4689-9527-7D30F2427016/0/test1.pdf

For part A, X-Y obviously adds to the top and bottom positions creating an octahedral molecule.  Part B, the H₂ cannot add to the molecule as H₂ must add cis due to its requirement of using a concerted mechanism.  Part B, the MeI, due to its polarity adds in an Sn2 mechanistic way which has an allowance for trans addition meaning the reaction will occur.  On Part C, the three reaction pathways asked for are concerted, Sn2, and radical. 
For part D, I believe that what they are after are three experiment which show the solvent, steric, and leaving group dependency on the rate of the reaction due to the Sn2 pathway.  I do not know if this is correct.  And even if it is correct, I am unsure what they want as for an answer.