Question

Write the name of the major organic product formed in the reaction of 1-pentene with hydrogen iodide.

• A. 1-iodopentane
• B. 2-iodopentane
• C. 3-iodopentane
• D. None of these

Answer 1

The correct option is B 2-iodopentane

1-pentene reacts with HI to form 2-iodopentane as the major product. The addition follows Markwonikoff's rule-the negative part $\left(B{r}^{-}\right)$ will be added to the less substituted carbon atom attached to the double bond.

$C{H}_2=CH-C{H}_{2}C{H}_{2}C{H}_3+HI\to C{H}_{3}CHI-C{H}_{2}C{H}_{2}C{H}_3$

The product formed is 2-iodopentane.

Hence, the correct option is B.