Question

How can I calculate the dilution factor using concentration?

Answer 1

In a solution the number of moles remains fixed if you dilute the solution. Use this mole method in which moles of both the volume of solution equal to each other. You will get a formula which we generally use in ionic equilibrium chapters and also in the practical. If you are diluting the solution it is general that molarity will decrease, that is concentration will decrease.

Complete step-by-step answer:
When we are making a solution we are adding an amount of solute in a proper amount of solvent to make a solution. Now to measure the concentration of that solution we have methods like mass percent, mole fraction, molarity and molality etc.

Now suppose we have calculated the concentration of that solution using molarity which is independent of temperature. Let’s say you add more solvent in that solution and if you have made the solution using water then you are adding water to the solution. So, on adding water the solution starts becoming dilute and dilute. That means particles of solute are decreasing in one liters of solvent. If we say in mathematical terms dilution can be performed using formula- ${M_1}{V_1} = {M_2}{V_2}$

So, now a question arises how to use this formula, see if suppose you have one molar $1\,M$ concentration solution and you have it in $1\,L$ of volume then you have the known values of the left hand side of solution. If you diluted the solution by making it volume from $1\,L$ to $1.5\,L$ then now the unknown variable will be only ${M_2}$ in the above equation.

Let’s start by putting values in the question ${M_1} = 1\,M$ , ${V_1} = \,1\,L$ and ${V_2} = \,1.5\,L$ , we have to find out the value of ${M_2}$ that is molarity of new solution which will form.
${M_2} = \dfrac{{{M_1}{V_1}}}{{{V_2}}} = \dfrac{{1\,M \times 1\,L}}{{1.5\,L}}$ = $\dfrac{{1\,}}{{1.5}}\,M = 0.666\,M$

It means on dilution molarity of solution becomes $0.666\,M$ and decreases.

Note: In solutions where you can see the color, there it is visible that the solution is diluting by the color difference the color of concentrated solutions are dark while in case of diluted solutions color becomes light. Always try to solve questions by taking molarity and taking it in $mol\,{L^{ - 1}}$ , sometimes there is no molarity given directly but you have to calculate it first and then put it in the formula.