Question

In a reaction A + B2 → AB2, identify the limiting reagent in the reaction mixture containing 5
moles of A and 2.5 moles of B.

Answer 1

Hint:

A limiting reagent is a reagent in a reaction which is used up completely in a reaction. It determines the amount of the product formed after the reaction because the reaction cannot proceed without it. Once we calculate the number of mol of each reactant in the reaction, the limiting reagent can be determined.

Complete step by step answer:

A limiting reagent in a reaction is the reagent which is used completely in the reaction. It is present in less quantity as compared to the other reagent. It determines the amount of the product formed because without the limiting reagent the reaction cannot proceed further. To identify the limiting reagent in a reaction we first need to balance the chemical equation of the reaction then calculate the number of mol of each reactant present in the reaction and compare how many mol of each reactant are required to produce the product. Thus, the reactant which is being used completely for producing the product is the limiting reagent. So, for the above given question,

A+B2→AB2

According to the equation, 1 mole of A reacts with 1 mol of B2.

So, 2.5 mol of B2 react with 2.5 mol of A and thus, 2.5 mole of A are lest unreacted and thus, B2 is the limiting reagent.