Devise electrochemical cells in which the following reactions could be made to occur. if liquid junctions are necessary, note them in the cell schematic appropriately, but neglect their effects.(a) h2o ⇄ h + + oh-(b) 2h2 + o2 ⇄ h2o(c) fe3+ + fe(cn)6 4- ⇄ fe2+ + fe(cn)6 3-(d) cu2+ + pb ⇄ pb2+ + cuwhat half-reactions take place at the electrodes in each cell? what is the standard cell potential in each case? which electrode is negative? would the cell operate electrolytically or galvanically in carrying out a net reaction from left to right?