MCQs

N₂ = 0.5 mol. H₂ required = 1.5 mol but available = 4 mol. Excess H₂ = 2.5 mol = 5 g.

ZnS ≈ 1 mol and O₂ = 1.5 mol. Stoichiometric mixture. ZnO = 1 mol = 81 g.

An excess reactant is supplied in greater quantity than required and remains after the reaction.

NH₃ = 2 mol, O₂ = 1.5 mol. O₂ limits. NO = 1.2 mol. Mass = 1.2 × 30 = 36 g.

Stoichiometric mixture. Cl₂ produced = 1 mol = 71 g.

NO = 2 mol and O₂ = 1 mol. Stoichiometric mixture. NO₂ formed = 2 mol.

Limiting reactants are identified by comparing available and required mole ratios.

Carbon is limiting. Si = 1.5 mol. Mass = 1.5 × 28 = 42 g.

245 g = 2 mol KClO₃. O₂ = 3 mol. Volume = 3 × 22.4 = 67.2 dm³.

Ca = 0.5 mol, H₂O = 2 mol. Water left = 1 mol = 18 g.

The limiting reactant determines how much of the excess reactant is consumed.

Al = 1 mol (limiting). Cr produced = 1 mol = 52 g.

CH₄ = 1.25 mol, O₂ = 0.625 mol. Oxygen is insufficient and is limiting.

Na = 2 mol, H₂O = 3 mol. Na is limiting. H₂ = 1 mol = 2 g.

O₂ is limiting. H₂O formed = (2/3) × 2 = 1.33 mol.

The limiting reactant determines the maximum yield regardless of excess reactant.

P₄ = 0.5 mol and Cl₂ = 3 mol. Required Cl₂ = 3 mol. Both react completely.

Fe = 2 mol, H₂O = 2 mol. Water is limiting. Fe₃O₄ = 0.5 mol. Mass = 0.5 × 232 = 116 g.

The limiting reactant determines the maximum amount of product that can be formed.