In chemistry, normality is one of the phrases used to explain the concentration of a solution. It is seldom related to the equivalent concentration of a solution. It is abbreviated as ''N.'' It is mainly used to determine the number of reactive species in a solution and during titration reactions and circumstances involving acid-base chemistry.

According to the usual explanation, normality is the number of gramme or mole equivalents of solute contained in one litre of a solution. The quantity of moles of reactive units in a chemical is what we mean when we say equivalent.

Let's understand the core concepts of Equivalent Concentration and normality of a solution in this article.

Formula for Normality

• Normality = [volume of solution in litres]-1 (number of gramme equivalents)
• Weight of solute = number of gramme equivalents [Equivalent weight of solute]-1
• N = Solute Weight (grammes) [Equivalent weight Volume (L)]
• N = Molarity [Equivalent mass]-1
• N = Molarity; Basicity = Molarity; Acidity = Molarity;
The letter N is frequently used to represent normalcy. Eq L-1 and meq L-1 are also used to express some additional normality units. In medical reporting, the latter is commonly employed.

What is the formula for calculating normality?

Students can use a few tricks to figure out how to calculate normalcy.

1. The first piece of advice for students is to collect information on the equivalent weight of the reacting substance or solute. To learn about molecular weight and valence, consult a textbook or reference book.
2. Calculate the number of gramme equivalents of the solute in the second step.
3. Students should keep in mind that volume is measured in litres.
4. Finally, using the procedure and changing the values, normalcy is calculated.

Equations of Normality

The normalcy equation, which can be used to estimate the volume of a solution needed to make a solution of different normality, is as follows:

Initial Normality (N1) + Initial Volume (V1) = Final Normality (N2) + Final Volume (V2) (V2)

If four distinct solutions with the same normalcy and volume are mixed, the resultant normality is;

[Va+Vb+Vc+Vd]-1 = [NaVa + NbVb + NcVc + NdVd]

When four distinct solutes with various molarities, volumes, and H+ ions (na, nb, nc, nd) are combined, the resultant normalcy is;

[Va+Vb+Vc+Vd]-1 = [naMaVa + nbMbVb + ncMcVc + ndMdVd]


What is transmitted in a chemical reaction determines the reactive capacity of a chemical species, such as ions or electrons. An equivalent is the value of a chemical that will respond with one mole of hydrogen ions in an acid-base reaction. One mole of electrons in oxidation-reduction (redox) processes is obtained or lost in a chemical reaction. The search for counterparts is dependent on the chemical species in question.

An element's oxidation state describes the number of electrons transported in reactions. The number of equivalents is equal to the oxidation, or valence states, of the following elements:

Calcium ion (Ca + 2) has a valence of 2 and has 2 equivalents.

(Al +3) ion: valence 3; number of equivalents = 3 Aluminum: (Al +3) ion: valence 3; number of equivalents = 3

The number of hydrogen ions transferred by a molecule is equivalent to acids. It is simple to find equivalent units for acids. In the chemical formulas below, look at the number immediately after the hydrogen (H). The number indicates how many equivalents per mole of that acid there are:

1 equivalent of hydrochloric acid (HCl)

H2SO4 (sulfuric acid): equivalents = 2

equivalents = 3 phosphoric acid (H3PO4)

equivalents = 1 nitric acid (HNO3)

It is the number of hydroxide ions (OH-) provided for a reaction in the case of bases, such as:

equivalents = 1 sodium hydroxide (NaOH)

equivalent = 2 barium hydroxide (Ba(OH)2)

A neutral solution is made by mixing equal amounts of acidic and basic solutions. One acid equivalence reacts with one base equivalence. The reactivity of the acid HCl and the base NaOH, both with one equivalent, is the same. In the case of two equivalents of H2SO4 and NaOH, it will take twice as much NaOH to react with the sulfuric acid.

Although molarity can calculate acid concentrations, it is a poor tool for analysing neutralisation reactions. Why? Because not all acids and bases can add (or subtract) the same quantity of hydrogen ions from a solution.

Equivalent Weight

The equivalent weight of a material containing a single reactive proton (or hydrogen ion) or a single reactive hydroxide ion can be thought of as that substance's weight (or mass). 

Acids, proton donors, fall into the first category, whereas bases, proton acceptors, fall into the second. Because some compounds can give or take more than one proton, the idea of equivalent weight is required because the material is effectively twice reactive for every mole present. 

The equivalent weight can be calculated using the following formula:

The ratio of a substance's molar mass to its valence is referred to as equivalent weight. Equivalence factor is another term for valence. The quantity of hydrogen atoms in an acid or hydroxide atoms in a base and the charge present in ionic forms determine the valence. 

The valence or equivalency factor in reduction/oxidation (redox) reactions are the number of electrons that an oxidising or reducing substance can absorb or donate is the valence or equivalency factor in reduction/oxidation (redox) reactions. Gram equivalent weight is defined as the equivalent weight expressed in grammes using molar mass in grammes.

Let's get some practice determining the equivalent weight for the following formulas:

Molar mass of H2SO4 = 98 g/mol
Looking at the formula, there are 2 hydrogen atoms, so "n" will be 2 when determining the equivalent weight:

Molar mass of NaCl = 58.5 g/mol
Looking at the formula, because there are no hydrogen or hydroxide atoms, the number of equivalents is 1 because there will always be at least one equivalent before a reaction can occur.

Molar mass of NaOH = 40 g/mol
In looking at the formula, there is 1 hydroxide (OH) atom, so the equivalent is 1.


Hope you liked the guide of equivalent Concentration and Normality of a Solution. I hope you understood the concept clearly. If you have any questions or queries relatedly, please drop them down in the comment section provided.