One half of an electrochemical cell consists of a pure nickel electrode in a solution of Ni2+ ions; the other half is a cadmium electrode immersed in a Cd2+ solution. (a) If the cell is a standard one, write the spontaneous overall reaction and calculate the voltage that is generated. (b) Compute the cell potential at 25C if the Cd2+ and Ni2+ concentrations are 0.5 and 103M, respectively. Is the spontaneous reaction still in the same direction as for the standard cell