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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: KH502 on May 18, 2015, 07:48:35 AM

Title: Reduction potentials
Post by: KH502 on May 18, 2015, 07:48:35 AM

Bars of copper (Cu) , silver (Ag) and iron (Fe) were immersed in 1M AgNO3, CuSO4 and CuCl2 solutions, respectively. The copper bar was covered with silver while silver and iron bars remained intact. The conclusion is that standard reduction potentials (E0)
change in the following order:

A. E(0) Fe(2+)/Fe > E(0) Cu(+2)/Cu > E(0) Ag(+)/Ag,
B. E(0) Fe(2+)/Fe < E(0) Cu(+2)/Cu < E(0) Ag(+)/Ag, :larrow:
C. E(0) Fe(2+)/Fe > E(0) Cu(+2)/Cu < E(0) Ag(+)/Ag,
D. E(0) Fe(2+)/Fe < E(0) Cu(+2)/Cu > E(0) Ag(+)/Ag,
E. E(0) Fe(2+)/Fe < E(0) Cu(+2)/Cu = E(0) Ag(+)/Ag

Souldn't the iron bar get oxidized by Cu2+ in th solution, which gets redused to solid Cu?
Cu2+ +2e- :rarrow: Cu 0,34 V
Fe2+ +2e- :larrow: Fe -0,44 V

Is the question wrong, or am I wrong? Please explain, thanks.

Title: Re: Reduction potentials
Post by: Borek on May 18, 2015, 09:10:46 AM

You are right, iron will get covered with copper.