What is the hybridisation of each carbon in $H_2C = C = CH_2$?

(N/A) The carbon atoms $1$ and $3$ are $sp^2$ hybridized because each is bonded to three atoms (two $H$ atoms and one $C$ atom) and participates in one double bond.
The central carbon atom $(C_2)$ is $sp$-hybridized because it is bonded to two carbon atoms via two double bonds.
In the structure of allene $(H_2C=C=CH_2)$,the two $\pi$ bonds are perpendicular to each other. The $2p_y$ and $2p_z$ orbitals of the central carbon atom $(C_2)$ are involved in the formation of $\pi$ bonds with the adjacent carbon atoms,leaving only the $2s$ and one $2p$ orbital for hybridization,resulting in $sp$ hybridization for $C_2$.