CBSE Class 12-science Answered

Normality can be defined as the number of gram equivalents of the solute dissolved per litre (dm³) of given solution. It is denoted by ‘N’ and mathematically represented as

N = Number of gram equivalent of solute / Volume of the solution in litres

Normality can be calculated from strength as, N = Strength in grams per litre / Eq. mass of solute

For a ‘w’ gram of the solute present in ‘V’ cm³ of a given solution,

N =( w / Eq. mass of the solute) x ( 1000 / V)

Hence, a solution of sulphuric acid having 0.68 gram of it dissolved in 100 cm³ of solution will have normality as follows, (Equivalent mass of sulphuric acid is 49)

N = (0.68 g / 49 g eq-¹) x ( 1000 cm³L^-1 / 100 cm³)

N = 0.14 g eq L^-1

Normality is particularly useful in titrations calculations.