Page 15 Flashcards
What is the most common mechanism for dehydrohalogenation?
A: The E2 mechanism.
What type of kinetics does the E2 mechanism exhibit?
A: Second-order kinetics.
What does the rate equation for an E2 reaction depend on?
A: The concentrations of both the alkyl halide and the base.
Rate equation: \text{rate} = k[\text{alkyl halide}][\text{base}] .
Why is the E2 mechanism considered a “concerted” reaction?
A: Because all bond breaking and bond formation occur in a single step.
Which two reactants are involved in the rate-determining step of an E2 reaction?
A: The alkyl halide and the base.
In the E2 mechanism, what happens to the β-hydrogen and the leaving group?
A: The β-hydrogen is removed by the base, and the leaving group departs simultaneously, forming a double bond.
How does the strength of the base affect the E2 mechanism?
A: A strong base is required to abstract the β-hydrogen effectively, making the E2 reaction proceed faster.
What is the molecularity of the E2 mechanism?
A: The E2 mechanism is bimolecular because the rate depends on two species (substrate and base)
What role does the leaving group play in the E2 mechanism?
A: The leaving group departs as the double bond forms, allowing the reaction to proceed.
What is the key difference between E2 and E1 mechanisms regarding reaction steps?
A: E2 is a single-step, concerted reaction, whereas E1 involves a two-step process with a carbocation intermediate.
