Question

Does pure water have a concentration?

Answer 1

Hint: Water (\[{{H}_{2}}O\]) is an inorganic, clear, tasteless, odourless, and virtually colourless chemical substance that is the primary ingredient of the Earth's hydrosphere and all known living species' fluids (in which it acts as a solvent). Even though it contains no calories or organic nutrients, it is necessary for all known forms of life. Each of its molecules has one oxygen and two hydrogen atoms linked by covalent bonds, as indicated by its chemical formula \[{{H}_{2}}O\].

Complete answer:
Molar concentration is a measurement of a chemical species' concentration in a solution, specifically a solute's concentration, in terms of the amount of substance per unit volume of solution. The number of moles per litre is the most widely used unit of molarity in chemistry.
\[c=\dfrac{n}{V}=\dfrac{N}{{{N}_{\text{A}}}V}=\dfrac{C}{{{N}_{\text{A}}}}\]
Here, n is the solute concentration in moles, N is the number of component particles in volume V (in litres), and ${{N}_{a}}$ is the Avogadro constant.
The mass-to-volume ratio is known as density. As a result, we may deduce that, based on the density of water.
Mass of pure water is 1 Kg
Volume of pure water is 1 L
We must now determine the number of moles of water in 1 kilogramme of water. The ratio of a material's weight to its gramme molecular mass can be used to compute the number of moles in the substance. The only difference between gramme molecular mass and molecular mass is that it has a unit – gramme.
The total of all the individual atomic masses may be used to compute the molecular weight of water. Water (\[{{H}_{2}}O\]) has two hydrogen atoms and one oxygen atom.
Oxygen has an atomic mass of 16.
2 hydrogen atoms have a mass of 12=2.
Water has a molecular mass of 16+2=18.
The molecular mass in grams is 18 gm.
Weight of pure water = 1 Kg = 1000 gm.
$=\dfrac{1000}{18}=55.56$ moles
Now, as we know, Molarity $=\dfrac{\text { Number of moles of }}{\text { Volume of the solution in litre }}$
 \[~\Rightarrow \]Molarity $=\dfrac{55.56 \text { moles }}{1 L}$
Pure water has a molarity of 55.56 moles per litre.

Note:
To concentrate a solution, either more solute (such as alcohol) or less solvent must be added (for example, water). To dilute a solution, however, one must either add additional solvent or lower the amount of solute. There is a concentration at which no more solute will dissolve in a solution unless two compounds are miscible. The solution is considered to be saturated at this stage.