A species having carbon with sextet of electrons and can act as electrophile is called

We need to identify the species in which carbon has a sextet of electrons and can act as an electrophile.

Understand what a "sextet of electrons" means.

A carbon atom normally has 4 valence electrons and achieves an octet (8 electrons) by forming 4 bonds. If carbon has only a sextet (6 electrons), it is 2 electrons short of an octet, meaning it has an empty p-orbital.

Analyze each option.

Carbon free radical: Has 7 electrons (3 bonds + 1 unpaired electron). This is a septet, not a sextet. It is reactive but primarily acts as a radical, not an electrophile.

Carbanion: Has 8 electrons (3 bonds + 1 lone pair). Carbon has a complete octet and a negative charge. It acts as a nucleophile (electron donor), not an electrophile.

Carbocation: Carbon has only 6 electrons (3 bonds, no lone pair). It has an empty p-orbital, making it electron-deficient. Since it seeks electrons to complete its octet, it acts as an electrophile (electron acceptor). This matches both criteria: sextet of electrons and electrophilic character.

Pentavalent carbon: This would have 10 electrons around carbon, which is not a sextet.

The correct answer is Option (3): carbocation.