Out of $CH_4, CaH_2, FeCl_2$ and $BeH_2$, which compound would produce the most strongly reducing aqueous solution?
Out of the hydrides, I would say that $CaH_2$ stands a good chance at being the strongest reducing agent, since the Ca-H bond energy is lowest (allowing the extremely reducing hydride to be released more readily into solution). The only rationale I can think up for this is the relative sizes of the other ion in the hydrides (Ca>Be>C) which implies that bond length is greatest in the calcium hydride (thus bond energy is lower). I am unsure as to how I should tackle the chloride compound. Much assistance is needed.