Question

X in the following reaction is –

CH₃ - C - H
Br₂ + || □(→┴CCl₄ ) X
H - C - CH₃
(a) (+) 2, 3-Dibromobutane
(b) (–) 2, 3-Dibromobutane
(c) Rac. 2, 3-Dibromobutane
(d) Meso-2, 3-Dibromobutane

Answer 1

X in the following reaction is –

CH₃ - C - H

Br₂ + || □(→┴CCl₄ ) X

H - C - CH₃

(a) (+) 2, 3-Dibromobutane

(b) (–) 2, 3-Dibromobutane

(c) Rac. 2, 3-Dibromobutane

(d) Meso-2, 3-Dibromobutane

Answer 2

X in the following reaction is :

Reaction :

CH₃ - C - H + Br₂ + □(→┴CCl₄ ) X

||

H - C - CH₃

• Br₂ in presence of CCl₄ with alkenes gives vicinal dibromides.

• Anti-addition is done about double bond.

• Bromine adds on to the trans but-2-ene leads to Meso-2, 3-Dibromobutane.

• Hence X in the following reaction is Meso-2, 3-Dibromobutane.