Aarti Gupta
Last Activity: 10 Years ago
Normality(N) – It is the number of gram equivalents of the solute present in 1000 ml or 1L of the solution.It is expressed as-
N = G-equivalents of solute/ volume of solution (L)
= Mass of solute/ GEM(solute) * vol.of sol.(L)
where, GEM is the gram equivalent mass which is the quantity of substance whose mass in grams is equal to its equivalent mass.For ex- equivalent mass of oxygen is 8 so its GEM will be 8g.
Formality(F) – It is the number of gram formula mass of solute dissolved per litre of solution.It is expressed as -
F = Number of gram formula mass of solute / volume of solution in litres
Formality,like molarity expresses concentration as moles of solute per litre of solution.Molarity is the concentration of particular species in solution, while formality is substance’s total concentration in solution without regard to its specific chemical form.If the substance dissolves without dissociating in ions,then there will be no difference between molarity and formality.Nowdays molarity is used in place of formality.
And the relation between molarity and normality is given as-
Molarity * Molecular mass(solute)= Normality * Equivalent mass(solute)