In a Mannich reaction, 0.40 mol of formaldehyde, 0.35 mol of piperidine, and 0.30 mol of acetophenone are mixed under acidic conditions. After work‑up, 0.20 mol of the Mannich product is isolated. Calculate the percentage yield based on the limiting reagent.

Step-by-step solution

1. Recognise the stoichiometry: one mole each reactant gives one mole product.
2. Identify the limiting reagent: acetophenone (0.30 mol) is the smallest amount.
3. Theoretical yield of product = 0.30 mol.
4. Actual isolated yield = 0.20 mol.
5. Percentage yield = (actual/theoretical)×100 = (0.20/0.30)×100 = 66.7\%.
6. Round to one decimal place: 66.7%.

Concept tested: Stoichiometry and yield calculation in Mannich reaction

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