What is the type of reaction illustrated by the following? CH3 —CH2 —CH2 —OH + HBr → CH3 —CH2 —CH2 —Br + H2O *

substitution
addition
hydrogenation
oxidation

The given reaction is a substitution reaction.

Explanation:

CH₃ - CH₂ -CH₂ - OH + HBr → CH₃ - CH₂ -CH₂ - Br + H₂O

When propanol is treated with hydrogen halide say HBr that is hydrogen bromide then the bromide ion from HBr replaces hydroxyl group in propanol, so it is called as substitution reaction, since -OH group is substituted by Br group. Mostly alcohols undergo nucleophilic substitution reaction.

Alcohols when treated with hydrogen halide -OH is substituted by  -Br group, so it is called as substitution reaction.

it forms an anion that has a larger radius. anions have a negative charge and are larger than the original atom.