Alcohols Phenols And Ethers Ques 35
35. Which of the following reaction (s) can be used for the preparation of alkyl halides?
[2015 RS]
(I) $CH_3 CH_2 OH+HCl\xrightarrow{\text{ anh. }} \xrightarrow{ZnCl_2}$
(II) $CH_3 CH_2 OH+HCl \longrightarrow$
(III) $(CH_3)_3 COH+HCl \longrightarrow$
(IV) $(CH_3)_2 CHOH+HCl \xrightarrow{\text{ anh. } ZnCl_2}$
(a) (I), (III) and (IV) only
(b) (I) and (II) only
(c) (IV) only
(d) (III) and (IV) only
Show Answer
Answer:
Correct Answer: 35.(a)
Solution:
(a)
Carbocation is formed as intermediate in the $S _{N_1}$ mechanism which these reaction undergoes. (III) Tertiary carbocation easily formed due to the stability.
(IV) In the presence of $ZnCl_2, 2^{\circ}$ carbocation is formed from 
NOTES
$ZnCl_2$ is a lewis acid and interact with alcohol. In the absence of $ZnCl_2$ formation of primary carbocation is difficult.
BETA
