Chapter 12.3, Problem 36LC

Interpretation Introduction

Interpretation: The limited and excess reagent needs to be explained.

Concept introduction: A reagent is a substance that is added to the reaction to start the reaction. This reagent can be limited or in excess depending upon its amount.

Answer to Problem 36LC

A limiting reagent is one which used up completely in the reaction and excess reagent remains in the reaction even after its completion.

Explanation of Solution

In a reaction, all reactants react together in a stoichiometric ratio to form a product which is also formed according to stoichiometry. Reactants can be limited or excess reagents.

For example:

  $2{\text{H}}_2+{\text{O}}_2\to 2{\text{H}}_{\text{2}}\text{O}$

• A limiting reagent is a reagent which completely used up in the reaction. The limiting agent even governs the reaction.
• An excess reagent is a reagent that is not completely used up in the reaction. Excess reagent left in the reaction even after completion of the reaction.

Conclusion

A limiting reagent is one which used up completely in the reaction and excess reagent remains in the reaction even after its completion.