Question

which compound can be oxidized to a carboxylic acid?

Explanation:

Step1: Recall oxidation rules

Primary alcohols can be oxidized to carboxylic acids. Secondary alcohols are oxidized to ketones and tertiary alcohols do not undergo oxidation under normal conditions.

Step2: Identify alcohol types

The first - compound is an alkene, not an alcohol. The second and fifth compounds are secondary alcohols. The third compound is a tertiary alcohol. The fourth compound is a primary alcohol ($\text{CH}_2\text{OH}$ group).

Answer:

The compound with the structure having $\text{CH}_2\text{OH}$ group (the fourth - one in the list)