Calculate the theoretical potential of each of the following cells. Is the cell reaction spontaneous as written or spontaneous in the opposite direction? a. Pt| Cr+ (2.00x104 M),Cr+(1.50x10-3 M)||Pb+(5.60x10- M) | Pb b. Pt|Fe+(3.00x10-2 M),Fe+(4.00x10-5 M)||Sn+(3.50x10- M), Sn4+ (5.50x104 M) | Pt