The concept of limiting reagent simplified

Introduction 

In a chemical process, the limiting reagent  is a completely consumed reactant when the reaction occurs. The above Reagent determines the level of product formed because the reaction could continue without it. Suppose an or so other reagents are present in the material than those needed to react with the limiting Reagent. In that case, the limiting Reagent should be defined to calculate the percentage yield of a reaction because theoretical yield is defined as the number of products obtained when the limiting Reagent completely reacts. 

Body

According to stoichiometry, a fixed number of reactants is required to complete a chemical process. Take a look at the following ammonia formation reaction:

2NH3  → 3H2 + N2 

In the above reaction, 3 moles of H2 must 1 mole of nitrogen gas is reacted with to 2 moles of ammonia But what if, produce 2 moles of ammonia. However, what if only 2 moles of hydrogen gas and 1 mole of nitrogen are available during the reaction?

That is the case. The total N2 can not be used. As a result, the H2 gas limits the reaction and is thus referred to as the limiting Reagent for this reaction.

Limiting Reagent Overview

This reactant, Overall, determines when the reaction would be completed. The amount of reactant required to react with some other element can be calculated using reaction stoichiometry. The limiting Reagent is determined by the mole ratio rather than the masses of the reactants present.

As shown in the illustration above, the limiting reactant is the main cause the reaction cannot continue because there is nothing left to react with the excess reactant.And during reaction, the reactant is completely consumed.

How to Locate a Limiting Reagent

Approach 1 for Identifying the Limiting Reagent

Determine the limiting Reagent by counting the moles of each reactant.

Identify the chemical reaction’s balanced chemical equation.

Convert all given data into moles (most likely, through the molar mass as a conversion factor).

Determine the mole ratio based on the information provided. Calculate and actual ratios.

Calculate the amount of product produced using the amount of limiting reactant.

Determine how much extra non-limiting Reagent remains if necessary.

Approach 2 for Finding the Limiting Reagent

Calculate and compare the amount of product produced from each reactant to determine the limiting Reagent.

For the chemical reaction, balance the chemical equation.

Convert the given data into moles.

To determine the mass of the product produced, use stoichiometry for each reactant.

The reagent which produces the least amount of the product is known as the limiting reagent.

The excess reagent is the reactant that produces the most product.

Subtract the total weight of excess Reagent given from of the total weight of excess Reagent consumed.to determine the amount of remaining excess reactant.

Examples of Limited Reagents

Consider the following reaction, which requires 1 mol of oxygen and 1 mol of hydrogen.

2H2O → 2H2 + O2

Because the reaction consumes hydrogen twice as quickly as oxygen, hydrogen is the limiting reactant.

For instance, 100g of hydrochloric acid is mixed with 100g of zinc. Determine the amount of hydrogen gas produced under standard laboratory conditions.

Solution:

The chemical formula for these reactions is shown below.

2HCl(aq) + Zn(s)  → ZnCl2(aq) + H2 (g)

Because excess zinc chloride is formed, the limiting Reagent, in this case, is hydrochloric acid. 

22.4l of H2 = 73g of HCl

yL of H2 = 100g HCl

100/73 y = (100 x 22.4)/73 y = 30.6L y/22.4 = 100/73 y = (100 x 22.4)/73 y = 30.6L

As a result, 33.6L of H2 is produced under standard laboratory conditions.

Conclusion

Limiting reactants are limiting factors that determine outcomes in chemistry and stoichiometry. Limiting reactants are chemical ingredients that limit the amount of product produced during a chemical process. The limiting reactant is the element or compound that is depleted or consumed first in a chemical process. Limiting reactants is also known as limiting reagents.

Chemical reactions necessitate specific ratios of substances that act as fuel to keep the reaction going. If one of those substances is depleted or consumed completely, the chemical reaction cannot be sustained and thus terminates, yielding only a limited amount of a product while an excess reactant remains.