Chlorine gas can be prepared in the laboratory by the reaction of hydrochloric acid with manganese (IV) oxide. 4HCl (aq) + MnO2 (s) ⟶MnCl2 (aq) + 2H2O (l) + Cl2 (g) A sample of 37.7 g MnO2 is added to a solution containing 46.3 g HCl. What is the limiting reactant? HCl MnO2

HCl is the limiting reactant.

Explanation:

The reactant that yields the lesser number of moles of product is the limiting reactant

Number of moles of MnO2 = mass of MnO2 / molar mass of MnO2

Number of moles = 37.7g/86.9368 g/mol = 0.4336 moles

From the reaction equation,

If 1 mole of MnO2 yields 1 mole of chlorine gas

0.4336 moles of MnO2 also yield 0.4336 moles of chlorine gas

For HCl

Number of moles of HCl = mass of HCl / molar mass of HCl

Number of moles = 46.3g/36.46 g/mol = 1.27 moles of HCl

If 4 moles of HCl yields 1 mole of chlorine gas

1.27 moles of HCl will yield 1.27*1/4 = 0.3175 moles of HCl

Hence HCl is the limiting reactant.