Hydrochloric acid can dissolve solid iron according to the reaction:
Fe(s) + 2 HCl(aq) → FeCl2(aq) + H2(g)
What minimum mass of HCl in grams dissolves a 2.8-g iron bar on a padlock? How much H2 is produced by the complete reaction of the iron bar?
Let us see, one mole (55.8 g) of Fe reacts with 2 moles (36.5*2 = 73 g) of HCL
so 2.2 g will react with 2.2*73/55.8...