Okay!
8.50molH, represents 8.50 moles of Hydrogen gas!
To convert from moles to volume multiply it by the ratio of L/molH
mol of anything in a conversion problem is always 1 unless you are going to an unknown! Try to memorize this, but the number you always put in for the # of liters in a conversion problem is 22.4L (L is a measure of volume)
8.50molH * (22.4 L/ 1 molH)
190.L of Hydrogen Gas.
Hope that helped!