TS EAMCET 11-Sep-2020 Shift 1 Solved Paper

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×‌

1mol

86.9g

=1.15mol of MnO2
Moles of HCl=100g×‌

1mol

36.5g

=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

=‌

0.25molesMnO2

1molesHCl

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.