Question

The molarity of solution containing \[50g\]of \[NaCl\]in \[500g\]of a solution and having a density of \[0.936g/c{{m}^{3}}\]is:
A. \[1.5M\]
B. \[1.4M\]
C. \[1.8M\]
D. \[1.2M\]

Answer 1

Hint: Molarity (M) is the amount of a substance in a certain volume of solution. Molarity is defined as the moles of a solute per litre of a solution. Molarity is also known as the molar concentration of a solution.

Complete step by step answer:
Here, we have given that \[50g\]of \[NaCl\], \[500g\]of solution and \[0.936g/c{{m}^{3}}\] as the density of the solution, hence the total mass of the solution is equal to
\[\Rightarrow \text{Total Mass} = 50g+500g=550g\]
Also, we know that density is defined as the mass per unit volume, hence
\[\Rightarrow Density=\dfrac{Mass}{Volume}\]
\[\Rightarrow 0.936=\dfrac{550}{Volume}\]
\[\Rightarrow Volume=\dfrac{550}{0.936}=587.6ml\]
Here we got the volume of the solution, hence we have to find the molarity of the solution by the formula,
\[\Rightarrow Molarity=\dfrac{\text{Given Weight.of.Nacl}\times 1000}{\text{Molecular Weight.of.Nacl}\times Volume(ml)}\]
\[\Rightarrow Molarity=\dfrac{50\times 1000}{58.5\times 587.6}\]
\[\Rightarrow Molarity=1.45M\]
Here we got the molarity of the solution as \[1.4M\].

So, the correct answer is Option B.

Additional Information:
In chemistry concentration refers to the amount of substance in a defined space. These are usually applied for solutions, concentration may be calculated for any mixtures. Other then molarity there is some more terms are used to represent the concentrations of a substance such as mass concentration(mass of solute per volume of the solution),mass percent(mass of solute per mass of solution represented in percentile), mole fraction(number of moles of one species/number of moles of total species in the mixture).et

Note:
Here we know that the term molarity is related to the concentration of solution. Other the molarity there is one more word exist, i.e. Molality the number of moles of solute per kilogram of the solvent.