Elimination reactions of alkyl halides are favoured over substitution by
- A. a high concentration of a strong base, a non aqueous solvent and a higher temperature
- B. dilute aqueous conditions at room temperature
- C. the use of a weak nucleophile in water
- D. cooling the mixture in ice
Explanation
Elimination has the higher activation energy and produces more particles, so heat and a strong base in ethanol push the reaction that way, while water and mild conditions favour substitution. The two pathways always compete, and a given reaction usually produces some of both products. Tertiary halides eliminate most readily because the carbon is too crowded for substitution.