Research has been conducted on molybdates as replacements for chromates in the surface treatment of various metals in order to reduce corrosion by the formation of a surface film of MoO,. The overall reaction with iron is 2Fe(s) + 3M00; (aq) + 6H*(aq) → Fe;Os(s) + 3M0O:(s) + 3H;0() Given the following AG; in calories per mole at 25°C: Fe,O; (s) =-177,100, MoO:(s) = -120,000, H;O (1) =-56,690, Mo0; (aq) --205,420 (a) Is the above overall reaction spontaneous under standard conditions? (b) Calculate the standard electrode potential for the above overall reaction. (c) Write an expression for the electrode potential as a function of molybdate ion concentration and pH.

Research has been conducted on molybdates as replacements for chromates in the surface treatment of various metals in order to reduce corrosion by the formation of a surface film of MoO,. The overall reaction with iron is 2Fe(s) + 3M00; (aq) + 6H*(aq) → Fe;Os(s) + 3M0O:(s) + 3H;0() Given the following AG; in calories per mole at 25°C: Fe,O; (s) =-177,100, MoO:(s) = -120,000, H;O (1) =-56,690, Mo0; (aq) --205,420 (a) Is the above overall reaction spontaneous under standard conditions? (b) Calculate the standard electrode potential for the above overall reaction. (c) Write an expression for the electrode potential as a function of molybdate ion concentration and pH.

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter22: Bulk Electrolysis: Electrogravimetry And Coulometry

Section: Chapter Questions

Problem 22.29QAP

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