Question

What favors elimination reactions?

Answer 1

See below..

Explanation:

To promote elimination, the base should readily abstract a proton but not readily attack a carbon atom.

A bulky strong base, such as tert-butoxide enhances elimination.

Higher temperatures also favor elimination in most cases, because more molecules are formed, and `S < 0`.
As the temperature increases, the free energy term, ,becomes more negative and more favorable for elimination.

To promote substitution, we need a good nucleophile with limited basicity: a highly polarizable species that is the conjugate
base of a strong acid.

Bromide (`Br^-`) and iodide (`I^-`) are examples of good nucleophiles that are weak bases and favor substitution.