Question

Rion 1 of 3 > Chlorine gas can be prepared in the laboratory by the reaction of hydrochloric acid with manganese(IV) oxide. 4 HCl(aq) + Mn0,() — MnCl, (aq) + 2 H,0(1) + Cl,() A sample of 39.3 g Mno, is added to a solution containing 47.1 g HCI. What is the limiting reactant? Mno OHCI What is the theoretical yield of CI? theoretical yield: g Cl, If the yield of the reaction is 82.3%, what is the actual yield of chlorine? actual yield: gCl2

Answer 1

Moles of MnO2 = mass in grams/molar mass = 39.3/87 = 0.452 moles

Similarly,

Moles of HCl = 47.1/36.5 = 1.29 moles

From balanced reaction;

1 mole MnO2 requires 4 moles of HCl

So, 0.452 mole MnO2 will require = 4 * 0.452 = 1.808 moles of HCl

However, available moles of HCl = 1.29 which is less than 1.808. Hence, HCl is limiting reagent and MnO2 is excess reagent. ....Answer

And, limiting reagent will drive the yield of product i.e. Cl2.

Again from balanced reaction;

4 moles HCl produces 1 mole of Cl2

So, 1.29 mole HCl will produce = 1.29/4 = 0.3225 moles of Cl2

Thus,

Mass of Cl2 produced ( theoretical yield ) = moles * molar mass = 0.3225 * 71 = 22.898 grams .....Answer

% yield = actual yield * 100 / theoretical yield

82.3 = x * 100 / 22.898

x = 18.845 grams

Actual yield = x = 18.845 grams ....Answer

Let me know if any doubts.