6 gms of magnesium (atomic weight = 24), reacts with excess of an acid, the amount of H2 produced will be ______________ gm?
Correct answer: A
Explanation
The reaction is Mg + 2HCl -> MgCl2 + H2. Moles of Mg = 6/24 = 0.25 mol. Since the ratio is 1:1 for H2, moles of H2 = 0.25 mol. Mass of H2 = 0.25 * 2 = 0.5 gm.