In a reaction: A + B2 → AB2 Identify the limiting reagent, if any, i

1.	In a reaction: A + B2 → AB2 Identify the limiting reagent, if any, in the following reaction mixtures. (i) 300 atoms of A + 200 molecules of B(ii) 2 mol A + 3 mol B (iii) 100 atoms of A + 100 molecules of B(iv) 5 mol A + 2.5 mol B(v) 2.5 mol A + 5 mol B
Answer» (i) According to the reaction, 1 atom of A reacts with 1 molecule of B. ∴200 molecules of B will react with 200 atoms of A, thereby leaving 100 atoms of A unreacted. Hence, B is the limiting reagent. (ii) According to the reaction, 1 mol of A reacts with 1 mol of B. ∴ 2 mol of A will react with only 2 mol of B leaving 1 mol of B. Hence, A is the limiting reagent. (iii) 1 atom of A combines with 1 molecule of B. ∴ All 100 atoms of A will combine with all 100 molecules of B. Hence, the mixture is stoichiometric and ther is no limiting reagent. (iv) 1 mol of atom A combines with 1 mol of molecule B. ∴ 2.5 mol of B will combine with only 2.5 mol of A. and 2.5 mol of A will be left unreacted. Hence, B is the limiting reagent. (v) 1 mol of atom A combines with 1 mol of molecule B. ∴ 2.5 mol of A will combine with only 2.5 mol of B and the remaining 2.5 mol of B will be left. Hence, A is the limiting reagent

In a reaction: A + B2 → AB2 Identify the limiting reagent, if any, in the following reaction mixtures. (i) 300 atoms of A + 200 molecules of B(ii) 2 mol A + 3 mol B (iii) 100 atoms of A + 100 molecules of B(iv) 5 mol A + 2.5 mol B(v) 2.5 mol A + 5 mol B

Answer»

(i) According to the reaction, 1 atom of A reacts with 1 molecule of B.

∴200 molecules of B will react with 200 atoms of A, thereby leaving 100 atoms of A unreacted. Hence, B is the limiting reagent.

(ii) According to the reaction, 1 mol of A reacts with 1 mol of B.

∴ 2 mol of A will react with only 2 mol of B leaving 1 mol of B. Hence, A is the limiting reagent.

(iii) 1 atom of A combines with 1 molecule of B.

∴ All 100 atoms of A will combine with all 100 molecules of B. Hence, the mixture is stoichiometric and ther is no limiting reagent.

(iv) 1 mol of atom A combines with 1 mol of molecule B.

∴ 2.5 mol of B will combine with only 2.5 mol of A. and 2.5 mol of A will be left unreacted. Hence, B is the limiting reagent.

(v) 1 mol of atom A combines with 1 mol of molecule B.

∴ 2.5 mol of A will combine with only 2.5 mol of B and the remaining 2.5 mol of B will be left.

Hence, A is the limiting reagent