Answer:
1-metal + acid → salt + hydrogen gas
e.g magnesium + dilute sulfuric acid → magnesium sulfate + hydrogen
Mg + H2SO4 → MgSO4 + H2
2-metal oxide + acid → salt + water
e.g zinc oxide + dilute hydrochloric acid → zinc sulfate + water
ZnO + H2SO4 → ZnSO4 + H2O
3-metal hydroxide + acid → salt +water
e.g zinc hydroxide + dilute nitric acid → zinc nitrate + water
Zn(OH)2 + 2HNO3 → Zn(NO3)2 + 2H2O