Question

Which of the following Alkyl Halide will undergo ${\mathrm{E}}_2$ elimination?

• A.

  

• B.

  

• C.

  

• D.

  

Answer 1

Answer: (A), (B)

Explanation for correct option

(A) and (B)

${\mathbf{E}}_{\mathbf{2}}$ elimination

• ${\mathrm{E}}_2$ elimination reactions are one-step reactions with a single transition state.
• ${\mathrm{E}}_2$ elimination reactions frequently occur with secondary and tertiary alkyl halides, while a hindered base is required in the case of primary halides.
• It is necessary for both leaving groups to be on the same plane.

(A) and (B)

• Figures are as follows:

• Since ${\mathrm{E}}_2$ reactions involve anti-elimination, the leaving group must have a proton at the beta position.

• The hydrogen atom is present in the complexes (A) and (B) in the opposite position to the leaving group.

The explanation for incorrect options

• The complexes in (C) and (D) do not have hydrogen atoms in the anti position of the leaving group.
• Thus, they will not undergo ${\mathrm{E}}_2$ elimination.
• Hence options (C) and (D ) are incorrect.

Therefore, the correct option is (A) and (B).