Answer:
Option C. 3.85g
Explanation:
2NH3 <=> N2 + 3H2
Molar Mass of NH3 = 14.0067+ (3x1.0078) = 14.0067 + 3.02352 = 17.03022g/mol
Mass of NH3 from the balanced equation = 2 x 17.03022 = 34.06044g
Molar Mass of H2 = 2x1.00784 = 2.01568g/mol
Mass of H2 from the balanced equation = 3 x 2.01568 = 6.04704g
From the equation,
34.06044g of NH3 produced 6.04704g of H2
Therefore, 21.7 of NH3 will produce = (21.7 x 6.04704)/34.06044 = 3.85g of H2