Question

What volume of concentrated hydrochloric acid (12.0 M HCl) is required to make 2.0 liters of a 3.0 M HCl solution?

5.0 liters

0.24 liters

0.50 liters

6.0 liters

Answer 1

So step one is to determine the moles of HCl to do this use the formula:
n=cv
Where n is the number of moles, c is the concentration which is equal to 3.0M and v is the volume in litres which is the 2.0L
Plug your numbers in and solve for n

Answer 2

Since we have the moles from the above step we can then use the same formula except we are going to use it to find v
So v=n/c
Where v is the volume you are solving for, n is the moles that we found above and c is the concentration which is the 12.0M

Answer 3

Just to clarify in the first step I should have said that we needed to find the moles of the 3.0M HCl as both concentrations are for HCl

Answer 4

So basically the steps would be;
1. Finding the number of moles in the final solution
That would be 3x 2= 6 moles ( use n=C x V)
2. Since we are given the concentration of the HCl we have to use we can easily find the volume . Use n= C x V
n= 6 moles. because the no. of final solution should be the same
We know n and C . Now it's just the matter of substituting the values and obtaining V ( V= 0.5L )