Write the cell reaction and electrode half-reactions and calculate the standard potential of each of the following cells:
(a) Pt|Cl2(g)|HCl(aq)||K2CrO4(aq)|Ag2CrO4(s)|Ag
(b) Pt|Fe3+(aq),Fe2+(aq)||Sn4+(aq),Sn2+(aq)|Pt
(c) Cu|Cu2+(aq)||Mn2+(aq),H+(aq)|MnO2(s)|Pt