Final answer:
The decision on whether a reaction will happen by SN2, E2, SN1, or E1 mechanisms depends on the structure of the substrate, solvent, nucleophile, and leaving group strength.
Step-by-step explanation:
The determination of whether a reaction follows SN2, E2, SN1, or E1 mechanisms is contingent upon various factors.
Substrate structure holds significance, as tertiary substrates exhibit a preference for E2 reactions, primary and methyl substrates lean towards SN2 reactions, and secondary substrates accommodate both SN2 and E2 reactions.
Solvent nature and nucleophile characteristics are pivotal, with polar protic solvents promoting SN2 and SN1 reactions, while polar aprotic solvents favor SN2 reactions.
In reactions where SN1 and E1 mechanisms compete, tertiary substrates readily undergo SN1 and E1 processes.
Secondary substrates may or may not engage in SN1 and E1 reactions, whereas primary substrates typically do not participate.
Leaving groups influence mechanisms, with strong bases serving as poor leaving groups and weak bases as effective leaving groups in SN2, E2, SN1, and E1 reactions.
These nuanced considerations collectively govern the course of chemical reactions in organic chemistry.
Complete Question:
The decision on whether a reaction will happen by SN2, E2, SN1, or E1 mechanisms depends on what factors?