Chapter 19, Problem 3E

Classify each of the following half-reaction equations as oxidation or reduction half-reactions:

a) $\text{Zn}\to {\text{Zn}}^{\text{2+}}+{\text{2e}}^{-}$

b) ${\text{2H}}^{+}+{\text{2e}}^{-}\to {\text{H}}_2$

c) ${\text{Fe}}^{\text{2+}}\to {\text{Fe}}^{\text{3+}}+{\text{e}}^{-}$

d) $\text{NO}+2{\text{H}}_{\text{2}}\text{O}\to {\text{NO}}_3^{-}+4{\text{H}}^{+}+{\text{3e}}^{-}$