A stoichiometric mixture yields a complete reaction.

• A. True
• B. False
• C. Sometimes
• D. Not determinable

Answer: (A)

A stoichiometric mixture has reactants in exactly the amounts required by the balanced equation, so there is no excess of any reactant to limit the reaction. In theory, this allows the reaction to proceed to completion, converting all reactants into products and yielding the theoretical amount of product. In combustion, for example, a stoichiometric fuel–oxidizer mix should burn completely to carbon dioxide and water under ideal conditions. Real systems can deviate due to factors like incomplete mixing, heat transfer limitations, or side reactions, but the idea of a stoichiometric mix is that complete reaction is the expected outcome in the ideal case.