Source: Extra Practice
If 22.4 liters of H2(g) is mixed with 11.2 liters of Cl2(g), both at STP, how many moles of HCl(g) will be formed after the reaction is complete?
Options
Option A is correct
1.0 mole
Option B
2.0 moles
Option C
0.5 mole
Option D
1.5 moles
Explanation
The balanced chemical equation is H2(g) + Cl2(g) → 2HCl(g). At STP, 1 mole of any gas occupies 22.4 L. Here, moles of H2 = 22.4/22.4 = 1.0 mol, and moles of Cl2 = 11.2/22.4 = 0.5 mol. According to the stoichiometry, 1 mole of H2 requires 1 mole of Cl2. Since we only have 0.5 mol of Cl2, Cl2 is the limiting reagent. The amount of product is determined by the limiting reagent: 1 mole of Cl2 produces 2 moles of HCl, so 0.5 mole of Cl2 will produce (0.5 × 2) = 1.0 mole of HCl.