Final answer:
In the reaction of 80.0 mmol of CH₂CH₂ with 80.0 mmol of Cl₂, assuming complete reaction to equilibrium and no reverse reaction, 80.0 mmol of CH₂CH₂Cl₂ would be formed. However, without the equilibrium constant, we can't definitively determine the amount at equilibrium.
Step-by-step explanation:
When 80.0 mmol of CH₂CH₂ (ethylene) and 80.0 mmol of Cl₂ (chlorine) are mixed in a reaction, the two substances can react to form CH₂CH₂Cl₂ (1,2-dichloroethane) until equilibrium is reached. The reaction is as follows:
CH₂CH₂ + Cl₂ → CH₂CH₂Cl₂
This is a typical example of a halogenation reaction where an alkene reacts with a diatomic halogen molecule to form a dihaloalkane. Assuming the reaction goes to completion, because we have an equimolar amount of reactants, we would form 80.0 mmol of CH₂CH₂Cl₂.
However, as we need to consider the possibility of equilibrium, if the reaction does not go to completion or is reversible, there could theoretically be a different ratio of products to reactants at equilibrium. Without knowing the specific equilibrium constant for the reaction under the given conditions, we cannot say for certain whether the answer is 0.0 mmol, 40.0 mmol, or 80.0 mmol of CH₂CH₂Cl₂. However, if the reaction were to proceed completely to the right with no reverse reaction, the correct answer would be (c) 80.0 mmol of CH₂CH₂Cl₂, as all of the ethylene and chlorine would be consumed.