Consider the following reaction: 2AI + 6HBr to 2AlBr_3+3H_2 what is the limiting reactant?


Consider the following reaction:

2AI + 6HBr &rarr 2AlBr3 + 3H2

What is the limiting reactant?

Balanced chemical equation:

A balanced chemical equation has the same number of atoms and charges on both the reactant and product sides. Once a chemical equation is balanced, various stoichiometric calculations can be determined, including the yield (percentage or theoretical), excess reagents, and limiting reagents. Of high importance in stoichiometric calculations is the number of moles, which can be found using:

{eq}n = \dfrac{m}{Mm} {/eq},

where n is moles, m is mass (g) and Mm is the molar mass (g/mol).

Answer and Explanation: 1

Limiting reactant:

The substance completely used up in a chemical reaction is known as the limiting reagent for that particular reaction. Once the substance is used up, the reaction no longer proceeds. The steps for finding limiting reagent are as follows:

  • Conversion of the given mass to moles.
  • Divide the moles by suitable stoichiometry (molar ratio) of that element or compound.
  • The smallest number of moles obtained will be the limiting reagent.

The given chemical equation is represented as follows:

{eq}{\rm{2Al}} + {\rm{6HBr}} \to {\rm{2AlB}}{{\rm{r}}_{\rm{3}}} + {\rm{3}}{{\rm{H}}_2}{/eq}

According to the reaction, two moles of aluminum are reacting with 6 moles of HBr, which means there are fewer moles of Al than HBr. Thus, all of the moles of Al will get completely consumed in the reaction, and HBr will be left after the completion of the reaction.

Therefore, the limiting reagent is Al .

Learn more about this topic:

Limiting Reactants & Calculating Excess Reactants


Chapter 9 / Lesson 5

In this lesson, you'll learn about limiting and excess reactants and how to determine which reactant is the limiting one in a chemical reaction when given the amount of each reactant, and also how to calculate the amount of product produced.

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