magnesium metal (0.100 mol) and a volume of aqueous hydrochloric acid that contains 0.500 mol of hcl are combined and react to completion. how many liters of hydrogen gas, measured at stp, are produced? mg(s) 2hcl(aq) → mgcl2(aq) h2(g)magnesium metal (0.100 mol) and a volume of aqueous hydrochloric acid that contains 0.500 mol of hcl are combined and react to completion. how many liters of hydrogen gas, measured at stp, are produced? mg(s) 2hcl(aq) → mgcl2(aq) h2(g)