Question

How are carbocations stabilized?

Answer 1

Surrounding alkyl groups are electron-donating (electron-releasing) groups, which means they supply negative charge into the central, positively-charged carbon.

This is called hyperconjugation; the `"C"-"H"` bonding-electron pairs donate electron density into the empty `p` orbital of the central carbon.

The more surrounding alkyl groups there are, the more thermodynamically stabilized the carbocation is.