Which of the following statements best describes a limiting reactant?
a. the reactant that is used up the least
b. the reactant that is used up the most
c. the reactant that is used up before the others
d. the reactant that is left over after the reaction

c. The reactant that is used up before the others

Explanation:

For example:

If we are given 100 g of and 100 g of calcium.

As can be seen from the chemical equation, 2 moles of hydrochloric acid react with 1 mole of calcium.

According to mole concept, 1 mole of every substance weighs equal to its molar mass.

Thus of of hydrochloric acid reacts with 40 g of calcium.

100 g of hydrochloric acid react with=of calcium

Thus HCl is the limiting reagent as it limits the formation of product and calcium is the excess reagent as (100-54.79)=45.21 g is left unreacted.

Thus HCl which is a limiting reagent will be used up before Calcium.