Calculate the standard cell potential for each of the following cells then write the overall reaction. (These rxns are given in reduction order for each half-cell.)
a. Au1+/Au//Cr3+/Cr c. Pd2+/Pd//PbSO4//Pb, SO42-
b. O2/OH1-//Cl2/Cl1- d. Ni2+/Ni//Ag1+/Ag