Limiting reagent In a chemical reaction, the limiting reagent is the reactant that determine, how much of the products are made. The other reactants are sometimes referred to as being in excess, since there will be some leftover after the limiting reagent is completely used up.
Given, unbalanced reaction,
Convert amounts to moles
Moles of
MnO2=100g×=1.15mol of
MnO2 Moles of
HCl=100g×=2.73mol of
HCl Actual ratio (molar ratio) of reactants
The actual ratio tells us that we have
0.42 moles of
MnO2 for every 1 mole of
HCl. In comparison, the stoichiometric ratio from our balanced reaction is below :
Stoichiometric ratio
=| 1 moles of N2 |
| 4 moles of HCl |
= This means we need at least
0.25 mole of
MnO2 for every mole of
HCl. Since, our actual ratio is greater then our stoichiometric ratio, we have more
MnO2 than we need to react with each mole of HCl. Therefore, HCl is our limiting reagent and
MnO2 is in excess.