Concept:

The reaction of an alcohol with a hydrogen halide (halogen acid like HCl, HBr, HI) is a nucleophilic substitution reaction where the -OH group is replaced by a halogen atom (-X).

Formula:

$$ \text{R-CH}_2\text{OH} + \text{HX} \xrightarrow{\text{ZnCl}_2} \text{R-CH}_2\text{X} + \text{H}_2\text{O} $$

Solution:

• The hydroxyl group of the primary alcohol is protonated and then leaves as water.



• The halide ion attacks the same primary carbon framework (typically via an \(\text{S}_N2\) mechanism for primary alcohols).



• Because the carbon skeleton does not rearrange under normal conditions, a primary alkyl halide is formed.

Why other options are incorrect:

The product is a halide, not an alcohol (eliminating A, B, and C). It remains primary, so it cannot be a secondary alkyl halide unless a rare hydride shift rearrangement occurred (which is not standard for simple primary alcohols).