Question

Fe would corrode easily in a damp environment in which both water and oxygen are readily available. Identify the most likely anodic and cathodic reactions, respectively, from the table below. What is the standard electrode potential difference? Standard Electrode Electrode Reaction Potential, V 3 + +1.420 Au 3eAu O2 + 4H + + 4e-_→ 2H2O Pt2ePt +1.229 +0.800 Increasingly inert (cathodic) +0.771 +0.401 O2 + 2H2O + 4e-_→ 4(OH-) Cu2eCu +0.340 2H+ + 2e 0.000 0.126 > H2 0.136 Ni2+ + 2e Co2+ + 2e > Ni 0.250 0.277 0.403 > Co 0.440 0.744 ncreasingly active (anodic) 0.763 Al3+ + 3e-→ Al 1.662 2.363 2.714 2.924 If both the anodic and cathodic reactions are controlled by activation polarisation, the overvoltages for the oxidation and reduction reactions can be expressed as 7a (oxidation) = β log (ilio) and (reduction)-β log (1/O), respectively, where β and 10 are positive constants for a particular half cell and i is the current density. If the equilibrium potential (i. e. when the circuit is open) for a particular half cell is Vo. draw schematically the curves representing the potential as a function of log (ilio) when the circuit is closed for both the oxidation and the reduction reactions. (Mark the axes and relevant quantities in the diagram clearly.)

Answer 1

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O1u reducthm 0.2 Eletvochsm' 3 부 2 3 RT