Question #57f70

1 Answer
May 5, 2015

A Standard Reduction Potential table should have the electrode potentials listed top to bottom from most negative to most positive.

(http://hyperphysics.phy-astr.gsu.edu/hbase/tables/electpot.html)

When this is the case, #Zn_((s))# is actually above #Cu^(2+)# in the table, since it has a more negative standard electrode potential.

The more negative an electrode potential is, the stronger a reducing agent will be. Likewise, the more positive an electrode potential is, the stronger an oxidizing agent will be.

#Zn_((aq))^(2+) + 2e^(-) -> Zn_((s))#, #E^0 = "-0.76 V"#

#Cu_((aq))^(2+) + 2e^(-) -> Cu_((s))#, #E^0 = "+0.16 V"#

A more negative electrode potential means is that #Zn_((s))# can reduce #Cu^(2+)#, or, In other words, a more positive potential means that #Cu_((aq))^(2+)# can oxidize #Zn_((s))#.

Simply put, #Cu^(2+)# is being reduced by #Zn_((s))#.

Check out these answers for a more detailed explanation on how standard electrode potentials work:

http://socratic.org/questions/please-let-me-know-which-is-one-of-the-following-reagents-is-capable-of-transfor

http://socratic.org/questions/i-do-not-know-how-i-can-use-standard-electrode-potentials-decide-which-of-the-fo-1