Srinivas Rao
Last Activity: 14 Years ago
Chemical substances donot react with each other in terms of moles. It means, 1 mole of A may react with 2 moles of B or with 3 moles of C or with X moles of Z. The proportion in which they react is uncertain, until and unless you know the stoichiometry of the reaction.
To avoid this ambiguity of proportions of reactants, chemists introduced the concept of Equivalent weights. Always one equivalent of one substance reacts with one and only one equivalent of the other substance. Means, chemical substances react in terms of their equivalents (or milli equivalents) and not in terms of moles.
Gram equivalent of an acid, base, reductant or oxidant is the mass of substance in gram that can transact Avagadro number of electrons. So, 1 equivalent of acid reacts with 1 eq of base or 1 eq of reductant reacts with 1 eq of oxidant.