Determine which of the following pairs of reactants will result in a spontaneous reaction at 25 celsius?
Pb2+(aq) + Cu(s)
Ag+(aq) + Br-(aq)
Li+(aq) + Cr(s)
Fe3+(aq) + Cd(s)
None of the Above.
I've tried using using tables like this http://ch302.cm.utexas.edu/images302/Electrochemistry_Reduction_Potentials.jpg to use the equation Ecell = Ecath - Eanode.
I'm hoping anyone could answer the question, and explain why each of them could be, or could not be spontaneous. (I know that an Ecell being positive results in spontaneity).
Here's my work:
Pb2+(aq) + Cu(s)
.34-(-.13) = .47
Ag+(aq) + Br-(aq)
.80 - (.76) = .04
Li+(aq) + Cr(s)
-.90-(-3.05) = 2.15
Fe3+(aq) + Cd(s)
-.04 - (-.81) = 77
None of the Above.
As you can see, they're all spontaneous. I'm wondering if I grabbed the wrong values from the above table. The question asks about ONE spontaneous reaction, from my calculations, they're all spontaneous.
@MichaelD.M.Dryden