The molarity is equal to the number of moles per L of solution. Multiplying the molarity and the volume will give us the number of moles of HCl.
n = (1 mol/L) x (2 L) = 2 moles
The molar mass of HCl is 36.45 g/mol. Multiplying this to the number of moles will give us the mass of HCl.
mass of HCl = (36.45)(2 mol) = 72.9 grams HCl
