What is meant by the term "limiting reagent"?

The term "limiting reagent" refers specifically to the reactant that is completely consumed during a chemical reaction, thus limiting the amount of product that can be formed. When two or more reactants are combined, the limiting reagent is the one that runs out first, causing the reaction to stop, even if there are other reactants still available in excess. This concept is crucial when calculating theoretical yields and understanding reaction stoichiometry, as it helps predict how much product can be obtained from the reaction based on the amounts of the reactants used.

Options that suggest the limiting reagent is the one in excess or relates to the rate of reaction are inaccurate, as those correlate more to other concepts in chemistry, such as reagent efficiency or kinetics rather than stoichiometry. Additionally, the mention of a product being formed first does not pertain to the definition of limiting reagents, which focuses solely on the reactants involved in the chemical process.