Hydrocarbons - Result Question 39
In the presence of peroxide, hydrogen chloride and hydrogen iodide do not give anti-Markovnikov addition to alkenes because
(2001, 1 M)
(a) both are highly ionic in nature
(b) one is oxidising and the other is reducing
(c) one of the steps is endothermic in both cases
(d) all the steps are exothermic in both cases
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Answer:
Correct Answer: 22. (c)
Solution:
In addition of $HBr$ to an alkene, in the presence of peroxide, both the propagation steps are endothermic :
$ HBr+HO^{\bullet} \longrightarrow H _2 O+Br^{\bullet} $
In case of addition of $HCl$ and $HI$, one of the propagation steps is endothermic, reaction fails to occur.
BETA
