Question

6. It is desired to make 5.00 liters of 0.400 M HCl solution from a more concentrated stock solution of concentration 14.0 M. Describe how this is done.

Answer 1

Firstly, calculate the volume of 14 M HCl solution must be diluted to make 5L of 0.400 M HCl solution.

The most important thing to keep in mind when it comes to dilution is that number of moles of solute must remain same at all times.

So, moles of solute in diluted solution = moles of solute in concentrated solution

C1V1 = C2V2 ----(1)

Where C1 , V1 is concentration and volume of diluted solution

C2V2 is concentration and volume of concentrated solution

Putting values in (1)

5 x 0.400 = 14 V2

V2 = 0.1428 L

So, to make 5 L of 0.400 M of HCl solution, add 0.1428 L of 14 M HCl in the standard flask and then dilute( add water) to make up volume upto 5L.