Question

How are electrolytic conductors classified?

Answer 1

Depending upon the degree of dissociation, electrolytes can be classified into the following two categories.

1. Strong electrolytes: Strong electrolytes are those that virtually entirely break down into ions in solution. These electrolytes experience almost 100% dissociation in solution, meaning their degree of dissociation is nearly equivalent to 1. Strong electrolytes include inorganic salts like NaCl, KCl, BaCl₂, NH₄NO₃, etc.; strong bases like NaOH, KOH, Ba(OH), etc.; and strong acids like HCl, HNO₃, H₂SO₄, etc.
   Almost one mole of K⁺ and one mole of Cl⁻ ions are present in the solution that results from dissolving one mole of KCl in water, along with almost no un-ionised KCl. In solution, the ions stay solvated. The dissociation reaction equations for strong electrolytes are expressed with a single arrow, as seen below, because the solution of a strong electrolyte has very few unionised molecules at equilibrium.
   \[\ce{KCl_{(aq)} -> K{^+_{(aq)}} + Cl^-_{ (aq)}}\]
   \[\ce{HCl + H2O -> H3O{^+_{(aq)}} + Cl^-_{ (aq)}}\]
2. Weak electrolytes: Weak electrolytes are those that do not dissociate significantly in aqueous solution. Their degree of dissociation is less than one because of partial dissociation. Weak electrolytes include organic acids acetic, oxalic, benzoic, etc., organic bases CH₃NH₂, C₂H₅NH₂, C₆H₅NH₂, inorganic acids HCN, H₃BO₃, some inorganic bases NH₄OH, Cu(OH)₂, etc., and some inorganic salts HgCl₂, (CH₃COO)₂Pb, etc..
   The majority of weak electrolytes are polar covalent substances that ionise weakly in solution. Both the ions and the undissociated molecules are present in their solutions, and there is equilibrium between them. For example,
   \[\ce{CH3COOH_{(aq)} + H2O_{(l)} <=> H3O{^+_{(aq)}} + CH3COO^-_{ (aq)}}\]
   \[\ce{NH3_{(aq)} + H2O_{(l)} <=> NH^+_{4(aq)}}\]