Question

Oxides of the active metals combine with acid to form water and a salt. I need an example of this type of reaction.

Answer 1

pick an active metal (Na, K, Ca). Make an oxide out of it. React it with an acid (HCl would be a good choice). See what products should be formed. It's a double displacement reaction.

Active metal:\[Na\]Active metal oxide:\[Na_2O\]Active metal oxide + acid:\[Na_2O + HCl \rightarrow\]Active metal plus acid yields water and salt:\[Na_2O + HCl \rightarrow H_2O + NaCl\] balance if you have to