Question

When ethane, c2h6, reacts with chlorine, cl2, the main product is c2h5cl, but other products containing cl such as c2h4cl2 are also obtained in small quantities. c2h6 + cl2 c2h5cl + hcl the formation of these other products reduces the yield of c2h5cl. using the stoichiometry given in the chemical formula above, calculate the percent yield of c2h5cl if the reaction of 150. g of c2h6 with 205 g of cl2 produced 172 g of c2h5cl?

Answer 1

Theoretical yield is the amount supposedly produced by the reaction if it was complete. The balanced chemical reaction is:

 C2H6 + Cl2 = C2H5Cl + HCl

We use the amounts given for the reactants as the starting point of the calculations to determine the limiting reactant. We do as follows:

150 g C2H6 ( 1 mol / 30.08 g ) = 4.987 mol
205 g Cl2 ( 1 mol / 70.9 g ) = 2.891 mol

Therefore, the limiting reactant would be Cl2 since it would be consumed completely first in the reaction. We use this for the theoretical yield.

2.891 mol Cl2 ( 1 mol C2H5Cl / 1 mol Cl2 ) = 2.891 mol C2H5Cl (THEORETICAL YIELD)
172 g ( 1 mol / 64.52 g ) = 2.666 mol C2H5Cl ( ACTUAL YIELD)

Percent yield = 2.666 / 2.891 x 100 = 92.21%