The concentration is 0.200 mol/L.
Step 1. Calculate the moles of hydrogen chloride
We can use the Ideal Gas Law to do this:
#color(blue)(bar(ul(|color(white)(a/a)pV = nRTcolor(white)(a/a)|)))" "#
We can rearrange this equation to get
#n = (pV)/(RT)#
In this problem,
Step 2. Calculate the concentration of the solution