The false statements are:
- Statement I: A primary carbocation is less stable than a tertiary carbocation. This is false because a tertiary carbocation is more stable due to alkyl groups providing inductive and hyperconjugative stabilization.
- Statement IV: Isopropyl carbocation is more stable than ethyl carbocation. This is false because ethyl carbocation is more stable than isopropyl carbocation, as the inductive effects of alkyl groups play a role.