Chapter 5.4, Problem 5.14P

Identify the species that is oxidized and the species that is reduced in each reaction.Write out half reactions to show how many electrons are gained or lost by each species.
a. $\text{Zn}\left(\text{s}\right){\text{ + 2 H}}^{\text{+}}\left(\text{aq}\right)\to {\text{Zn}}^{\text{2}}\left(\text{aq}\right){\text{ + H}}_{\text{2}}\left(\text{g}\right)$

b. ${\text{Fe}}^{\text{3}}\left(\text{aq}\right)\text{ + Al}\left(\text{s}\right)\to {\text{Al}}^{\text{3}}\left(\text{aq}\right)\text{ + Fe}\left(\text{s}\right)$

c. ${\text{2 l}}^{\text{-}}{\text{+Br}}_{\text{2}}\to {\text{l}}_{\text{2}}+2{\text{Br}}^{\text{-}}$

d. $\text{2AgBr}\to {\text{2 Ag + Br}}_{\text{2}}$