REVERSIBLE AND IRREVERSIBLE REACTIONS

             REVERSIBLE REACTIONS;

      Reversible reaction is the reaction which can go in either direction. In reversible reactions none of reactants is completely used up and so the reaction does not going into completion. Means that reactants form products and at the same time products form reactants, as shown in the diagram below;                             

       Example of reversible reaction is formation of ammonium chloride and then dissociates into ammonia and chloride gase. Ammonia is an alkaline gas while hydrogen chloride gas is acidic. Ammonia is less dense than hydrogen chloride and difuse faster. There fore turns the wet red litmus paper into blue. Hydrogen chloride gas diffuses more slowly and turns the blue litmus paper red much later.

 The two gases recombine on cooling to form solid ammonia chloride. Heating of amonnia chloride is reversible chemical reactions.

IRRIVERSIBLE REACTIONS

    Irriversble reaction take place in only one direction and go on completion. The irreverble reactions proceed until at least one of the reactant used up completely. In these reactions products can not react back to form a reactants.

                                     

    Examples of irriversble reaction include a metals such as Na, Mg, K and so on when reacts with dillute acid to form salt and hydrogen gas as shown in the picture above
 
                        Mg + 2HCl  > MgCl2 + H2


 Asses yourself;

1) Explain the meaning of each of the following items
         
     a) reversible reaction

     b) activation energy

    c) catalyst

   d) irreversible reactions


2) Explain the following factors on how affect rate of chemical reaction.

      a) pressure

      b) catalyst

      c) temperature

     d ) Concentration

     e) surface area ( nature of reactants)