Mg(s) + H2SO4(aq) MgSO4(aq) + H2(g)
With bases (metal oxides and hydroxides)
The base dissolves in the acid and neutralises it. A salt is formed.
H2SO4(aq) + CuO(s) CuSO4(aq) + H2O(l)
With metal carbonates
With metal carbonates, effervescence occurs, salt, water and carbon dioxide gas is produced.
2HCl(aq) + CaCO3(s) CaCl2(s) + H2O(l) + CO2(g)
H+1 + OH-1 HOH
Acid + Base Water + Salt (double replacement)
HCl (aq) + NaOH (aq) HOH (l) + NaCl (aq)
H2SO4 (aq) + KOH (aq) 2 HOH (l) + K2SO4 (aq)
HBr (aq) + LiOH (aq)
H2CrO4 (aq) + NaOH (aq)
HNO3 (aq) + Ca(OH)2 (aq)
H3PO4 (aq) + Mg(OH)2 (aq)
The hydrogen ion H+(aq) does not exist as such in aqueous solutions. Hydrogen ions combine with water molecules to give a more stable species, the hydronium ion H3O+.
HCl(aq) + H2O(l) < ========= H3O+(aq) + Cl-(aq)
Acids can contain different numbers of acidic hydrogens, and can yield different numbers of H3O+ ions in solution.
HCl in stomach
H2SO4 in car batteries, as drying agent’
HNO3 in manufacturing of fertilizers
Ethanoic acid in food industry
Fatty acids in soap making
Ascorbic acid in medicine
Ammonium salts are decomposed when mixed with a base eg sodium hydroxide. The ammonia is readily detected by its pungent odour (strong smell) and by turning damp red litmus blue.
NaOH + NH4Cl ==> NaCl + H2O + NH3
Ionically: NH4+ + OH- ==> H2O + NH3
This reaction can be used to prepare ammonia gas and as a test for an ammonium salt.
Alkali's are used to produce the insoluble hydroxide precipitates of many metal ions from their soluble salt solutions.
2NaOH(aq) + CuSO4(aq) ==> Na2SO4(aq) + Cu(OH)2(s)
ionically: Cu2+(aq) + 2OH-(aq) ==> Cu(OH)2(s)
This reaction can be used as a simple test to help identify certain metal ions.
On the left and middle of the Periodic Table are the basic metal oxides eg Na2O, MgO, CuO etc
They react with acids to form salts. e.g
2HCl + MgO ------------ MgCl2 + H2O