Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

Environmental decay of historical buildings and outdoor works of art is an incre

ID: 581351 • Letter: E

Question

Environmental decay of historical buildings and outdoor works of art is an increasing problem. The Statue of Liberty on Ellis Island was constructed of an iron skeleton covered with a copper exterior, with layers of asbestos as insulation between the copper and iron. Because the Statue is composed of two dissimilar metals, redox mediated corrosion occurred when the asbestos wore away and the iron contacted the copper. The Statue was refurbished in the 1980s to repair the existing corrosion and prevent more from happening. Answer the following question concerning the Statue. 3. (a) Given the following reduction half-cell potentials, calculate the standard potential (Ecel) for a voltaic cell consisting of copper and iron. E Ted0.44 pored = + 0.34 2+ Note:for a complete redox reaction to occur, you will need to shift the direction of one of these half reactions, and also shift the sign of the given E red value to obtain a halfcell Eox in the direction where the full reaction is found to be favorabl>0 (b) Which metal is corroding in the Statue, copper or iron?

Explanation / Answer

a]

Fe -----> Fe+2 + 2e-      Eo = 0.44

Cu+2 + 2e- ----> Cu        Eo = 0.34

Net reaction :

Fe + Cu+2 ----> Fe+2 + Cu

Eo cell = 0.44+0.34 = 0.78 V

b] Iron is corroding in the stature

Since Fe is oxidising to Fe+2 by Cu+2