Question

DDT, an insecticide harmful to fish, birds, and humans, is produced by the following reaction:
$2C_6{H}_{5}Cl\left(chlorobenzene\right)+C_{2}HOC{l}_3\left(chloral\right)\to C_{14}{H}_{9}C{l}_5\left(DDT\right)+H_{2}O$
In a government lab, 1142 g of chlorobenzene is recated with 485 g of chloral.
Which reactant is limiting? Which is in excess?

Answer 1

$1142g$ $C_6{H}_{5}Cl\left[\frac{1mol{C}_6{H}_{5}Cl}{112.56g{C}_6{H}_{5}Cl}\right]=10.15$ mol $C_6{H}_{5}Cl$

$485g$ $C_{2}HOC{l}_3\left[\frac{1mol{C}_{2}HOC{l}_3}{147.88of{C}_{2}HOC{l}_3}\right]=3.29$ mol $C_{2}HOC{l}_3$

$10.15$ mol $C_6{H}_{5}Cl\left(\frac{1mol{C}_{2}HOC{l}_3}{2mol{C}_6{H}_{5}Cl}\right)=5.075$ mol $C_{2}HOC{l}_3$

$3.29$ mol $C_{2}HOC{l}_3$ $\left(\frac{1molDDT}{1mol{C}_{2}HOC{l}_3}\right)\left(\frac{354.48gDDT}{1molDDT}\right)=1.17\times {10}^{3}gDDT$ .

The limiting reagent is $C_{2}HOC{l}_3$ and excess reagent is $C_6{H}_{5}Cl$ .