Magnesium reacts with hydrochloric acid (HCl) as follows. Mg(s) + 2HCl(aq) -->MgCl(2)+H(2)(g) How many milliliters of hydrogen gas are produced by the reaction 0.020 mol of magnesium with excess of hydrochloric acid at STP? 0.448 mL 0.45 mL 448 mL 450 mL