Chemical properties of acids :
1) Active metals react with acids and liberate hydrogen gas
Zn + HCl → ZnCl2 + H2 ↑
2) Acids react with bases to form salt and water.
HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(I)
3) Acids react with metallic oxides to form salt and water.
MgO(s) + 2HCl(aq) → MgCl2(aq) + H2O(I)
4) Acids react with carbonates and hydrogen carbonates and release carbon dioxide gas.
CaCO3(s) + 2HCl(aq) → CaCl2(aq) + H2O(I) + CO2(g) ↑
Ca(HCO3)2(I) + 2HCl(aq) → CaCl2(aq) + 2H20((| + 2CO2(g) ↑