which of these metals will replace aluminum in a solution containing an aluminum compound?
tin, zinc, barium, or silver?
The Reactivity Series By studying replacement reactions we can arrange the metals in decreasing order of reactivity. The reactivity series list the different metals (and hydrogen) in order of their decreasing tendency to lose electrons in water solutions at specified temperatures. Hydrogen is on the list because it behaves as though it were a metal in certain reactions. Metals found above hydrogen will replace hydrogen in acid solutions, while those below will not.
As we know the tendency of metals to lose electrons depends chiefly on the nuclear charge and on the atomic radius of the metal atom. The reactivity series may be used to make reasonable predictions concerning the reactivity of different metals. According to the table, for example, aluminum will replace mercury in an aqueous solution of a mercury compound. Silver will not replace tin.
Li K Ba Sr Ca Na Mg Al Mn Zn Cr Fe Cd Co Ni Sn Pb *H Sb As Bi Cu Ag Pd Hg Pt Au
Most Reactive ---à Least Reactive
http://www.sciencebyjones.com/chemical_reactivity.htm
so the answer would be Ba