Question

In the reaction, $Ether\stackrel{Cold}{\to }HIROH+R^{\prime }I;$
if R contains $3$ carbon atoms, the number of carbon atoms in R' may be:

• A. $1$ or $2$
• B. $4$
• C. $1,2$ or $3$
• D. $2$ or $4$

Answer 1

The correct option is A $1$ or $2$

By studying the mechanism of the reaction, it is clear that an $S_{N}2$ pathway is involved with $I^{-}$ as the nucleophile. As the nucleophile $I^{-}$ itself is pretty large, it will always prefer to attack the less bulkier side of the ether thus producing a higher alcohol and a lower alkyl halide.
Since, $R$ of the alcohol part contains 3 carbon atoms, then $R^{\prime }$ should contain 1 or 2 carbon atoms.
Hence, Option A is the correct answer.