In fact the most concentrated hydrochloric acid you can buy is approx. 32%32% "w/w"w/w, and this is about 10.6*mol*L^-110.6⋅mol⋅L−1. Anyway we will go with the terms of the question.
Here we use the ratio, "concentration"="moles of solute"/"volume of solution"concentration=moles of solutevolume of solution.
And thus "moles of solute"="concentration"xx"volume"moles of solute=concentration×volume.
We want 500.0xx10^-3*Lxx2.00*mol*L^-1=1*mol500.0×10−3⋅L×2.00⋅mol⋅L−1=1⋅mol with respect to HClHCl.
And so we take the quotient, (1.00*mol)/(12.0*mol*L^-1)xx10^3*mL*L^-11.00⋅mol12.0⋅mol⋅L−1×103⋅mL⋅L−1
=83.3*mL=83.3⋅mL.
And so we take 83.3*mL83.3⋅mL of conc. acid, and we add approx. 420*mL420⋅mL of water. The order of addition is VERY important.
Remember what I said about diluting conc. acid: "If you spit in acid it spits back."If you spit in acid it spits back.