You'd need 250. mL of your solution to get that many moles of hydrochloric acid.
This means that, if you get 1 mole of something in 1 L of solution you'll get a 1 M solution.
Let's play a little with this concept. By the same reasoning, if you get 12 moles of
Now let's say you get 12 moles of
If you start with 3 moles of
THis means that, to get a molarity that's 4 times bigger, you need a volume 4 times smaller. Automatically, this means that you'd need 250. mL, or 1/4th of aliter, to get a 12 M solution with 3 moles of solute.
For more complex calculations, you'll have to use the formula for molarity
In this case, you'd get
Expressed in mL, the answer will be