Question

What major product is formed when heptyne is treated with Br2 in CCl4?

Select one:

a. E-1,2-dibromoheptene

b. 1,1-dibromoheptene

c. Z-1,2-dibromoheptene

d. 2,2-dibromoheptene

Answer 1

Answer:A 1,2-dibromoheptene

Explanation:

Answer 2

Answer:

Option A is the Answer.

Explanation:

Treatment of alkyne with Bromine in the presence of $CCl_4$ produces a trans product that is, a alkenyl bromide.

$CH_3 \ CH_2 \ CH_2 \ CH_2 \ CH_2 - C = CH \frac {(CCl_4)}{(Br_2 )} >  CH_3 \ CH_2 \ CH_2\ CH_2 \CH_2\ -CBr = CHBr$

E-1, 2-dibromoheptene

It is a trans intermediate on further halogenations produces a tetrabromopentane.  

It is an electrophilic expansion response in which the triple bond breaks to turn into a twofold bond and creates a dibromoalkene (E-1,2 dibromoheptene), and on further expansion, the twofold bond turns into a solitary bond and delivers a tetrabromoalkane.