Oxidation tends to start at tertiary carbon atoms because free radicals here are more stable, so last longer and are attacked by oxygen.
2.
Oxidation tends to start at tertiary carbon atoms because the free radicals formed here are more stable and longer lasting, making them more susceptible to attack by oxygen.
3.
Also, if the chloride ion is not attached to a tertiary carbon atom or secondary carbon atom, then the carbocation formed ( R + ) will undergo a carbocation rearrangement reaction.