which type of hybridisation of each carbon is there in the compound? \(\mathrm{CH}_{3}-\mathrm{CH}=\mathrm{CH}-\mathrm{CN}\) (a) \(\$_{1}^{3}, s p_{2}^{2}, s p^{2}, s p_{3}\) (b) \(s p^{3}, s p^{2}, s p^{2}, s p^{3}\) (c) \(s p^{3}, 5 p^{2}, s p^{3}, 5 p^{3}\) (d) \(s p^{3}, s p^{2}, 3 p, 5 p^{3}\)

In organic chemistry, sp3 hybridization is a common way in which carbon atoms arrange their electrons for bonding. When a carbon atom has four single bonds, it combines one s orbital and three p orbitals, forming four equivalent sp3 hybrid orbitals. These orbitals point towards the corners of a tetrahedron, resulting in bond angles of approximately 109.5 degrees.

This hybridization can be found in molecules like methane (CH4) and ethane (C2H6), as well as in the first carbon of the given compound. Each hybridized orbital contains one electron, and these orbitals overlap with the orbitals of hydrogen or other carbons to form strong sigma bonds.

When discussing sp2 hybridization, think of carbon atoms involved in double bonds. Here, one s orbital and two p orbitals merge, creating three sp2 hybrid orbitals that lie in a plane, with angles of roughly 120 degrees between them. The remaining unhybridized p orbital is perpendicular to this plane, which participates in pi bonding.

This is the case for the second and third carbons in our compound, CH3-CH=CH-CN. The carbon atoms involved in the double bond use their sp2 hybrid orbitals to form sigma bonds with adjacent atoms and the unhybridized p orbital for the pi bond of the double bond. The pi bond is weaker than the sigma bond and provides the double bond characteristic reactivity.

Sigma (σ) bonds are the result of head-on orbital overlap, creating a bond that is symmetrical around the bond axis. They are strong and permit free rotation of bonded atoms. In contrast, pi (π) bonds are formed by side-to-side overlap of unhybridized p orbitals, occurring in conjunction with sigma bonds in double and triple bonds.

In our compound, the first carbon forms only sigma bonds indicative of an sp3 hybridization. However, the second and third carbons form both sigma and pi bonds. Sigma bonds are formed with sp2 hybridized orbitals, while the pi bond is formed from the parallel overlap of the remaining p orbitals. This pi bond restricts the rotation of bonded atoms, which is characteristic of double-bonded structures.