A

\[\ce{HCI}\] y \[\ce{NaOH}\]

B

\[\ce{Mg}\] y \[\ce{Ca}\]

C

\[\ce{Na}\] y \[\ce{CO2}\]

D

\[\ce{NH3}\] y \[\ce{KOH}\]

E

\[\ce{H20}\] y \[\ce{Cu}\]