# Normality and Molarity

**NORMALITY:** Normality is one way to express the concentration of the solution

It is the number of gram equivalents of a solute present in one litre of solution.

**w = Mass of solute in gram **

**V = Volume of solution in ml**

**E = Equivalent weight of solute**

**The equivalent weight of Solute: **It is the number of parts by weight of the substance that combines or displaces, directly or indirectly, 1.008 parts by mass of hydrogen or 8 parts by mass of oxygen, or 35.5 parts by mass of chlorine. It can be calculated as

(i) Equivalent mass for elements = Atomic mass / Valency

(ii) Equivalent mass for acids = Molecular mass / Basicity of acids

(iii) Equivalent mass for bases = Molecular mass / Acidity of base

(iv) Equivalent mass for salts = Formula mass / (Valency of cation) (No. of cations)

(v) Equivalent mass for oxidising agents = Formula Mass / No. of electrons gained per molecule

vii) Equivalent weight of radicals = Formula mass of radical / No. of units of charge

**On dilution of the solution**, the number of equivalents of the solute is conserved, and thus, we can apply the formula: **N _{1}V_{1} = N_{2}V_{2}**

**Relation between Normality and Molarity:**