So for a dilution, you want to use the dilution formula as shown below.
is the initial concentration
is the initial volume
is the desired concentration or final concentration
is the final volume needed to reach C2
So in your scenario, the 1 molar solution of HCl is your C1
. Your initial volume is how much of the HCl is going to be used. C2
is the final concentration you want. Then you substitute the values into the equation and solve for V2
, which is now the total volume needed to get to a concentration of C2
Now to find how much water is needed to dilute HCl, you just do V2
. That would give you the amount of water needed to reach C2
from the original volume.
Hope that helps.
Please correct me if I have done anything wrong.