(What is Normality in Chemistry)– Usually gram equivalent is a measure of concentration per liter of weight. The gram equivalent mass is a measure of the reactive potential of a molecule. The normalcy of the solution is determined by the involvement of the solute in the reaction. The corresponding concentration of the solution is also known as normality.
Normality Equation :
The normality (N) molar concentration C divided by the similarity factor Freq is:
n = c / fade
A more general equation is Normality(N), equal to the gram equivalent weight divided by the liter of the solution:
N = grams equivalent weight/liter of solution (often expressed in g/L)
Or the scholar can be multiplied by the number of equivalents:
n = scholar x equivalent
Units of Normality :
In terms of normalcy, the capital letter N is used to denote concentration. It can also be expressed as eq/l (equivalent to per liter) or mek/l (0.001 N multivalent per liter, usually reserved for medical reporting).
Common example :
For acid reactions, a 1 M H 2 SO 4 solution will have normality (N) of 2 N because there are 2 moles of H+ ions present per liter of solution. For sulfide precipitation reactions, where the SO4- ion is the important part, the same 1 M solution of H2SO4 will have a normality of 1N.
Example problem :
For the reaction: find the normality of 0.1 M H 2 SO 4 (sulfuric acid).
H2SO4 + 2 NaOH → Na2SO4 + 2 H2O
According to the equation, 2 moles of H+ ions (2 equivalents) from sulfuric acid react with sodium hydroxide (NaOH) to form sodium sulfate (Na2SO4) and water. Using the equation:
n = scholar x equivalence n = 0.1 x 2n = 0.2 n
Don’t get confused by the number of moles of sodium hydroxide and water in the equation.
Read This Also
Since you have been given the amount of acid, you do not need additional information. You need to understand how many moles of hydrogen ions are participating in the reaction. Because sulfuric acid is such a powerful acid, you already know that it dissociates fully into its ions.
Potential issues with using N for concentration :
Although normality is a useful unit of concentration, it cannot be used for all situations because its value depends on the equivalence factor which can change depending on the type of chemical reaction of interest. For example, a solution of magnesium chloride (MgCl2) may have 1 N for Mg 2+ ions, yet 2 N for Cl ions. While n is a good unit to know, in actual laboratory work it is not used interchangeably or for molality. It contains the values of acid-base titrations, precipitation reactions, and redox reactions. 1/feq is an integer number in acid-base and precipitation processes. In redox reactions, 1/Feq can be a fraction.