Mole concept



  • what is the relation between 'molarity' and 'normality'?



  • N=M×i where i= number of equivalents/mol, to deduct i one should have the equation, for example in these acid-base reactions:

    H2SO4(ac) + NaOH (ac)-> NaHSO4(ac) + H2O(l)
    H2SO4(ac) + 2NaOH(ac) -> Na2SO4(ac) + 2H2O(l)

    Regarding the acid H2SO4, i= 1(eq/mol) for the first reaction because 1 mol of acid gives off 1 mol of protons to the base to form the product and in the second reaction i=2 because there are 2 mols of protons per mol H2SO4 accpted by 2 moles of NaOH to form the product, so if there is a 1 M solution of H2SO4, for reaction 1) the normality of the solution is 1 N and in reaction 2) the normalityof the solution is 2 N.

    Respect of the base NaOH, i=1 both times because NaOH can only furnish 1 mol of OH-ions or accept 1 H+ from the acid so always N= M with i=1 eq/mol

    The conclusion is that there’s no fixed relationship and it is needed to inspect the chemical reaction (using the equation) to figure out the relationship between the two units of concentration.


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