What makes one carbocation more stable than another?

Answer 1

The more carbons a carbocation is attached to, the more stable the carbocation because it allows the positive charge carried by the carbocation to be spread amongst the attached carbon atoms. A tertiary carbocation (attached to 3 carbon atoms) is more stable than a secondary carbocation (attached to 2 carbons) which is more stable than a primary carbocation (attached to only 1 carbon).