posted by Jake .
Using the following spontaneous reactions, classify the 3 metals involved (Cr, Sn, Al) according to increasing reductant properties.
a) 2Cr + 3Sn2+ 2Cr3+ + 3Sn
b) Al + Cr3+ Al3+ + Cr
With no arrows how in the world do I know the reactants from the products?
Anyway, you know these are spontaneous reactions so you know Cr displaces Sn^2+ and Al displaces Cr^3+ so the series would be Al, Cr, Sn with the strongest reducing agent being at the top.