In a Mannich reaction, 0.30 mol of formaldehyde, 0.25 mol of dimethylamine, and 0.20 mol of acetophenone are mixed under acidic conditions. After work‑up, 0.15 mol of the Mannich product is isolated. Calculate the percentage yield based on the limiting reagent.

Step-by-step solution

1. Determine stoichiometry: the Mannich product requires 1 mol each of formaldehyde, dimethylamine, and acetophenone per product molecule.
2. Identify the limiting reagent: acetophenone = 0.20 mol < 0.30 mol (formaldehyde) and 0.25 mol (dimethylamine).
3. Theoretical maximum yield = 0.20 mol of product.
4. Actual yield = 0.15 mol.
5. Percentage yield = $(0.15/0.20)\times 100$.
6. Thus the yield is 75%.

Concept tested: Stoichiometry of Mannich reaction

Published 15 September 2026 · Last updated 16 September 2026 · How this solution was prepared and checked