Find Chlorine gas formed and which reactant remains in excess. (Use dimensional analysis)

Question

Chlorine can be generated by heating together calcium hypochlorite and hydrochloric acid.Calcium chloride and water are also formed.

A. If 50.0 g Ca(OCl)₂ and 275mL of 6.00 M HCl are allowed to react, how many grams of chlorine gas will form?

B. Which reactant , Ca(OCl)₂ or HCl, remains in excess and in what mass.

Answer 1

Ca(OCl)₂ + 4HCl ===> 2Cl₂(g) + CaCl₂ + 2H₂O

moles Ca(OCl)₂ present = 50.0 g x 1 mole/143 g = 0.3497 moles

moles HCl = 0.275 L x 6.00 mol/L = 1.65 moles

0.3497 moles Ca(OCl)₂ x 2 mole Cl₂/mole Ca(OCl)₂ x 71 g/mol Cl₂ = 49.7 g Cl₂ formed

1.65 moles HCl x 2 mole Cl₂/4 moles HCl x 71 g/mole Cl₂ = 58.6 g Cl₂ formed

Since Ca(OCl)₂ is limiting, 49.7 g Cl₂ is formed, and HCl remains in excess.

0.3497 moles Ca(OCl)2 x 4 mole HCl/mole Ca(OCl)2 = 1.399 moles HCl used up

HCl remaining = (1.65 moles HCl - 1.399 moles) x 36.5 g/mole HCl = 9.49 g HCl left over