Chemistry (NMK)

    Eqv. Mass of A   =   Mass of A

    Eqv. Mass of B         Mass of B


    à This relation tells that the combining mass reactants is always in the ratio of their equivalent mass. This law is also known as LAW OF CHEMICAL EQUIVALENCE.

    @ Atomic Mass = Eqv. Mass X Valency

    @ ‘Gram Eqv.’ or ‘Eqv.’

    à Eqv. mass of a substance, expressed in gram is ‘one gram equivalent’ or ‘1 eqv.’
    Equivalent Mass of a compound
                     a) Eqv. mass of acid
                               = Molecular Mass of acid
    where Basicity of an acid is defined as no. of H+ ions displaced or OH- ions combined per molecule of the acid.
    Eqv. mass of H2SO4  = 98 / 2 = 49
                       b) Eqv. mass of Base
                                = Molecular Mass
    where acidity of the base is defined as the no. of H+ ions consumed or OH- ions displaced per molecule of the base.
             Eq. Mass of Ca(OH)2 = 74/2 = 37


                       c) Eqv. mass of Salt
                                                         Molecular Mass of Salt                        
                                    Total no. of charge in basic or acid radical per molecule
              Eq. mass of  Na2CO3   =  106 / 2  =  53