Question

What is the concentration of a 1:10 dilution of a 2.5 M solution of NaCl? How would you prepare exactly 100 ml of such a solution?

Answer 1

Answer: The concentration of the solution is 0.25 M

Explanation:

Let the volume of solution of 2.5 M NaCl be 10 mL

We are given:

Dilution ratio = 1 : 10

So, the solution prepared will have a volume of = $\frac{10}{1}\times 1000=100mL$

To calculate the molarity of the diluted solution, we use the equation:

$M_1V_1=M_2V_2$

where,

$M_1\text{ and }V_1$ are the molarity and volume of the concentrated NaCl solution

$M_2\text{ and }V_2$ are the molarity and volume of diluted NaCl solution

We are given:

$M_1=2.5M\\V_1=10mL\\M_2=?M\\V_2=100mL$

Putting values in above equation, we get:

$2.5\times 10=M_2\times 100\\\\M_2=\frac{2.5\times 10}{100}=0.25M$

Hence, the concentration of the solution is 0.25 M