Termolecular reaction

• A. Two reactants.
• B. Four reactants.
• C. One reactant and two products.
• D. Three reactant molecules.

Answer: (D)

Termolecular reactions involve three reactant molecules colliding simultaneously to form products. This is a third-order process, with the rate in an elementary step proportional to the product of the three reactant concentrations: rate ∝ [A][B][C]. In practice, true termolecular elementary steps are rare because three-body collisions are unlikely, so many reactions that look termolecular proceed via two-body collisions with a third body helping stabilize an intermediate. The description that best fits this concept is a process where three reactant molecules come together to react.