Chapter 21, Problem 87SAE

Listed are several pairs of substances. For some pairs, one or both members of the pair react individually with water to produce a gas. For others, neither member of the pair reacts with water. The pair for which each member reacts with water and yields the same gaseous product is
(a) Al(s) and Ba(s); (b) Ca(s) and ${\text{CaH}}_{\text{2}}\left(\text{s}\right);$ (c) Na(s) and ${\text{Na}}_{\text{2}}{\text{O}}_{\text{2}}\left(\text{s}\right);$ (d) K(s) and ${\text{KO}}_{\text{2}}\left(\text{s}\right)$ ; (e) ${\text{NaHCO}}_{\text{2}}\left(\text{s}\right)$ and HCI(aq.)