Daniel Arthur
What is Normality?
Normality in chemistry is very important term & very useful to making reagents for analysis.
Unfortunately, many professional even experienced professionals don’t have the clear basics concept of normality.
I guarantee you after reading this article you have solid understanding about normality & its calculation.
Defination: Normality in chemistry means numbers of equivalents per liter of solution.It is denoted by symbol N.
Normality Formula:
Normality in chemistry defined by below formula:
Formula: Normality(N) = Numbers of equivalent(n) / Volume of Solution(L)Another very important factor is how to calculate the equivalents of substance.You can easily calculate equivalent by dividing molecular weight by its valency.
Let’s take example and calculate numbers of equivalents of Hydrochloric Acid & Sulphuric Acid.
Formula: Molecular Wight(gm/mol) / ValencyWhat is valency in chemistry?
The “valency” or “valence” of an atom or molecule described as how may hydrogen atoms it can bond with. In our example,
Hydrochloric Acid – HCl have a one hydrogen atom so, the equivalents of Hydrochloric Acid is 36.46/1 = 36.46
Sulphuric Acid – H2SO4 have two hydrogen atoms so, the equivalents of Sulphuric Acid is 98/2 = 49
How to calculate normality of concentrated hydrochloric acid(HCl)?
First, note down three things form packing label of solution:
Use below formula to calculate normality of any commercially available liquid solution:
Normality = Specific gravity × Percentage of purity in decimal × 1000 ÷ Equivalent weightIf you see label of reagent bottle of hydrochloric acid you will get below three values:
- Specific gravity – 1.18
- Assay – 35.4 (convert it into decimal divided by 100. 35.4/100 =0.354)
- Molecular Weight – 36.46 gm/mole (Calculate equivalent weight divided by its valency. valency of hydrochloric acid is 1. that means 36.46/1 =36.46)
Put the above values in formula,
Normality = 1.18 × 0.354 × 1000 ÷ 36.46 = 11.46 N
How to calculate normality of concentrated sulphuric acid?
If you see label of reagent bottle of sulphuric acid you will get below three values:
- Specific gravity – 1.84
- Assay – 98 (convert it into decimal divided by 100. 98/100 =0.98)
- Molecular Weight – 98.08 gm/mole (Calculate equivalent weight divided by its valency. valency of sulphuric acid is 2. that means 98.08/2 =49.04)
Put the above values in formula,
Normality = 1.84 × 0.98 × 1000 ÷ 49.04 = 36.77 N
Normality Calculator For Concentrated Liquid Chemical
This is very handy tool for science student to make reagents for analysis. You can easily calculate normality of any concentrated acid or base liquid solution by using this normality calculator.
In conclusion, Normality or equivalent concentration of the solution indicates how many equivalent are present per liter of solution.
Frequently Asked Questions:
Normality and Molarity both are same?
No, Both are different. Normality gives the concentration in equivalent per liter while the Molarity gives in moles per liter.
What is the formula of Normality?
Formula: Normality(N) = Numbers of equivalent(n) / Volume of Solution(L)
What is the formula of Molarity?
Formula: Molarity(M) = Moles of Solute(M) / Volume of Solution(L)
