Chapter 18, Problem 18E

Determine whether or not each redox re action occurs spontaneously in the reverse direction.
a. ${\text{Ca}}^{\text{2}+}\left(aq\right)+\text{ Zn}\left(s\right)\to \text{Ca}\left(s\right)+{\text{Zn}}^{\text{2}+}\left(aq\right)$

b. ${\text{2Ag}}^{+}\left(aq\right)+\text{Ni}\left(s\right)\to \text{2Ag}\left(s\right)+{\text{Ni}}^{\text{2}+}\left(aq\right)$

c. $\text{Fe }\left(s\right)+{\text{Mn}}^{\text{2}+}\left(aq\right)\to {\text{Fe}}^{\text{2}+}\left(aq\right)+\text{Mn}\left(s\right)$

d. $\text{2 Al}\left(s\right)+{\text{3 Pb}}^{\text{2}+}\left(aq\right)\to {\text{2 Al}}^{\text{3}+}\left(aq\right)+\text{3 Pb}\left(s\right)$