1. A steam turbine is an important component of an electricity generator. The turbine blade is usually made of nickel. From the following table of EMFs, list three coating materials that can protect the nickel blade from corrosion.
2. In following figure, assume that (1) electrical conduction only occurs through the metallic wire, (2) there is no moisture in the ambient air, (3) electrodes (Mg, Fe, and Cu) are free of defects, and (4) only Fe and Cu are submerged in the electrolyte. Use the above table of EMFs to answer the following questions (1) Draw a flow of electron in the metallic wire. Is there an electrical current to the Mg electrode? Give a physical explanation to your answer.
(2) Which electrode corrodes? Give a physical explanation to your answer.
(3) If the electrode Mg is replaced by Au, which electrode is an anode (Fe, Cu or Au)? Give a physical explanation to your answer.
Electrode Reaction Au 3+-+ 3e Au O2 4H 4e 2H2O Pt Ag Fe3+ e 2+ O2 2H2O 4e 4 (OH Cu2+ 2e Cu 2H+ 2e H2 Pb 2e Pb Sn 2e Sn Ni 2e Ni Co2+ 2e Co Cd 2e Fe2+ 2e Fe Cr 3e Zn 2e Zn Al Standard Electrode Potential, V CV) +1.420 +1,229 +1.2 +0.800 +0.771 +0.401 +0.340 0.000 0.126 0.136 0.250 0.277 0.403 40 0.744. 0.763 1.662
