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Equilibrium

Question
CBSEENCH11006491

Discuss different types of electrolytes.

Solution
Depending upon the degree of ionisation, there are two types of electrolytes.
(i) Strong electrolyte: A substance which dissociates almost completely into ions in its aqueous solution is known as strong electrolyte". Even though the amount of strong electrolyte may be small, the concentration of ions in aqueous solution is high and thus electrical conductivity is also high e.g. HCl, HNO3, H2SO4, NaOH, KOH, NaCl, NaNO3. There is no equilibrium in their aqueous solutions since only a few molecules may be unionised. Their ionised form may be rep- resented as,
HCl space plus space straight H subscript 2 straight O space space rightwards arrow space space straight H subscript 3 straight O to the power of plus space space plus space Cl to the power of minus
HNO subscript 3 plus straight H subscript 2 straight O space space space rightwards arrow space space space straight H subscript 3 straight O to the power of plus space plus space NO subscript 3 superscript minus
(ii) Weak electrolyte: A substance which dissociates to a small extent in its aqueous solution is known as a weak electrolyte. Even though the amount of weak electrolyte may be large, the concentration of ions in solution is low and thus electrical conductivity is-low, for example, HF, H2CO3, H2C2O4, H3PO4, CH3COOH, HCN. Since weak electrolytes are feebly ionised in their aqueous solution, an equilibrium is set up between the ion3 and unionised electrolyte. For example.
               CH subscript 3 COOH space plus space aq space space rightwards harpoon over leftwards harpoon space space space CH subscript 3 COO to the power of minus left parenthesis aq right parenthesis space plus space straight H to the power of plus left parenthesis aq right parenthesis
space space HCN space plus space aq space rightwards harpoon over leftwards harpoon space space space straight H to the power of plus left parenthesis aq right parenthesis space plus space CN to the power of minus left parenthesis aq right parenthesis