Irreversible Reactions

Definition

Chemical changes in which reactants convert to products and where the products cannot convert back to the reactants #ChemistryDefinitions

Characteristics of Irreversible Reactions

  • proceed only in 1 direction (unidirectional) i.e. forward direction
  • can proceed to completion (i.e. all reactants undergo reaction to form products)
  • in the chemical equation for these reactions, a ” ” is placed between reactants and products

Example

i) neutralisation reactions between strong acids and strong bases Acids + Bases (Metal oxides and Metal hydroxides)

ii) precipitation reactions

  • e.g. between sulfuric acid and barium nitrate solution

ii) displacement reactions of metals (type of redox)

iv) thermal decomposition of some compounds.

v) ionisation (or dissociation) of strong acids and alkalis in aqueous solution


Reversible Reactions

Definition

Reversible reactions are chemical changes in which entier amount of reactants is not converted into products.

Symbol

reversible arrow:

  • forward reaction is one that goes to right
  • backward reaction is one that goes to left

Characteristics of Reversible Reactions

  • can be started from either side
  • reactions proceed in both directions i.e. both forward and backward reactions take place simultaneously.
  • reactants and products are never fully consumed. they are constantly reacting and being produced.

Example

i) ionisation (or dissociation) of weak acids and alkalis in aqueous solution

ii) thermal decomposition of some compounds. e.g. thermal decomp. of ammonium chloride to produce ammonia and hydrogen chloride gas. another example is thermal decomposition of hydrated copper(II)sulfate to produce anhydrous copper(II) sulfate