Question

How can I determine whether an E or an SN reaction will occur?

Answer 1

The more steric prevention you have, the almost certain the response will be the first request. For example $E_1$ or then again ${S_N}1$, relying upon the temperature. You may consider the present circumstance an "aloof" replacement or disposal.

Complete step by step solution:
${S_N}2$ Grows to Nucleophilic Substitution response and as its rate-deciding advance includes both the reactants for example second request-response henceforth 2. In this sort of responses, a nucleophile assault from the backside for example from the contrary side of leaving bunch shapes a progress state (three-sided pyramidal) trailed by debilitating of the connection between focal carbon and departing the gathering lastly, a nucleophile subbed item and if the atom is chiral the response prompts inversion.E2 responses are disposal response, in which nucleophile goes about as a base and digests a proton which prompts the development of the alkene.
Going to your inquiry, the item framed itself is distinctive in two systems by which you can separate between the two. Notwithstanding, the two response instruments do have numerous similitudes, for example, both requiring great leaving gatherings, and the two systems are deliberate. ${S_N}2$ Responses require a decent nucleophile and E2 responses require a solid base. Notwithstanding, a decent nucleophile is regularly a solid base. Since the two responses share a significant number of similar conditions, they regularly contend with one another.

Note: The higher the temperature, the almost certain end happens. The lower the temperature, the almost certain replacement happens. For instance, an auxiliary alkyl halide in ethanol will presumably do basically ${S_N}1$., yet not transcendently ${S_N}1$.