Coupon Accepted Successfully!



Salt is a compound formed by the partial or complete replacement of the replaceable hydrogen ion of an acid by a metallic ion or a radical.
For Example
  1. Complete replacement of hydrogen ion of an acid
    2NaOH + H2SO4 Description: 32762.jpg Na2SO4 + 2H2O
  2. Partial replacement of metallic ion or ammonium ion radical
    NaOH + H2SO4 Description: 32764.jpg NaHSO4 + H2O
  • Radicals are groups of atoms that take part in chemical reactions as a single unit, e.g. ammonium (NH +4), erchlorate (ClO 4), cyanide (CN) etc.
  • A complexion is a charged species in which an atom or group of atoms is covalently bound to a metal, e.g. [Cu(NH3)4]2+.

Salt is formed by the reaction between an acid and a base. The reaction between an acid and a base to give salt and water is called neutralisation reaction.

Classification of Salts

Salts are classified into different types as shown in Table


Types of Salts


Types of Salts
Normal salts
Salt that has neither hydrogen nor hydroxyl in its formula
Sodium nitrate (NaNO3)
Sodium chloride (NaCl)
Sodium acetate (CH3COONa)
Sodium carbonate (Na2CO3)
Sodium sulphite (Na2SO3)
Sodium sulphate (Na2SO4)
Acid salts
Salt that has hydrogen in its formula
Sodium bicarbonate (NaHCO3)
Sodium bisulphite (NaHSO3)
Sodium hydrogen sulphate (NaHSO4)
Basic salts
Salt that has hydroxyl in its formula
Basic copper nitrate Cu(OH)NO3
Basic copper chloride Cu(OH)Cl
Basic lead nitrate Pb(OH)NO3
Double salts
Salt that contains two different positive ions
Dolomite, CaMg(CO3)2
Mohr’s salt, FeSO4 · (NH4)2 SO4 · 6H2O
Alum, K2SO4 · Al2(SO4)3 · 24H2O
Complex salts
Salt that contains a complex ion that does not dissociate in solution
Potassium ferricyanide, K3[Fe(CN)6]
Potassium mercuric iodide, K2[HgI4]
Sodium silver cyanide, Na[Ag(CN)2]
Mixed salts
Salt that contains two or more negative or positive radicals
Bleaching powder, CaOCl2
Sodium potassium carbonate, NaKCO3


Uses of Salts
  1. Ammonium chloride (NH4Cl) is used as an electrolyte in dry cells.
  2. Sodium bicarbonate (NaHCO3) is used in baking powder and in the manufacture of glass.
  3. Sodium chloride (NaCl) is used for seasoning and preserving food.
  4. Calcium chloride (CaCl2) is used as a drying agent to absorb moisture and in freezing mixtures.
  5. Silver bromide (AgBr) is used in making photographic film.
  6. Potassium nitrate (KNO3) is used in the manufacture of explosives and fertilisers.
  7. Sodium nitrate (NaNO3) is used in the manufacture of fertilisers and nitric acid.

Calculation of the Strength of Acids/Bases

Acidity or basicity of a solution is quantitatively measured in terms of the molar concentration of hydronium/hydroxyl ion, i.e. [H3O+] and [OH].

Soren Sorensen, in 1909, suggested a convenient and practical method of expressing the molar concentration of H3O+ in terms of pH.
Mathematically, pH is expressed as
pH = log10 [H3O+]
Thus, pH is defined as the negative logarithm to base 10 of hydronium ion concentration in a solution.
The pH range for different solutions is 0 to 14, which is represented in Figure 8.1.

Test Your Skills Now!
Take a Quiz now
Reviewer Name