Question

How to calculate concentration of solution when it’s diluted?

Answer 1

The concentration of the solution is diluted means a certain amount of solvent is added to make the dilution. This also means that the initial and final values of volume and concentration are different. One can put the known values in the relation formula and find out the concentration of the diluted solution.

Complete step by step answer: 1) First of all, we will see the relation formula between the initial values and the final values as below,
${C_1}{V_1} = {C_2}{V_2}$
Where ${C_1}$ is the initial concentration of the solution before the dilution
${V_1}$ is the initial volume of the solution before the dilution
${C_2}$ is the final concentration of the solution after the dilution
${V_2}$ is the final volume of the solution after the dilution
2) Now if we need to calculate the concentration of the solution after the dilution of the solution, we can do that by simply taking the final concentration term on one side as below,
${C_2} = \dfrac{{{C_1}{V_1}}}{{{V_2}}}$
3) Now let us take an example where we need to calculate the concentration of the solution after the dilution. Suppose a solution of ${\text{HCl}}$ has initial concentration as $0 \cdot 5Mol/L$ and volume as ${\text{400 mL}}$. This solution is diluted to the volume of ${\text{1200 mL}}$ then what will be the concentration of solution after the dilution.
Now let use the formula as below,
${C_2} = \dfrac{{{C_1}{V_1}}}{{{V_2}}}$
Now let us put the known values in the above formula as below,
${C_2} = \dfrac{{0 \cdot 5 \times 0 \cdot 4}}{{1 \cdot 2}}$
We have taken all the volume values in liters as per the formula,
Now by doing the calculation we get,
${C_2} = 1 \cdot 667Mol/L$
Therefore, the concentration of the solution after the dilution is ${\text{1}} \cdot {\text{667 Mol/L}}$.

Note:
For the calculation of the concentration of diluted solution there is an instrument called a UV spectrophotometer. The product of concentration and volume in both the initial and final stages is always equal. In the laboratory a concentrated stock solution is diluted for using it for experiment purposes.