Question

The terminal carbon atom in $2 - butene$ is ……………. hybridized.

Answer 1

The molecular formula of $2 - butene$ is $C{H_3}{\text{ - }}CH = CH{\text{ - }}C{H_3}$. It has four carbon atoms. Hybridization is the intermixing of atomic orbitals for forming new hybrid orbitals.

Complete step by step answer:
2 ̶ butene is an acyclic alkene with four carbon atoms. It is the simplest alkene exhibiting cis/trans isomerism. That is, it exists as two geometric isomers, cis-2-butene and trans-2-butene. The cis isomer has both the functional groups on the same side of the double bond. Hence, it has a dipole moment. In the trans isomer the functional groups are on the opposite sides of the double bond. Both the isomers behave similarly in most of the reactions. The two isomers are extremely difficult to separate because of the proximity in their boiling points. While cis-2-butene is a polar molecule, trans-2-butene is non polar. Heat or irradiation with light can bring about the conversion of one geometric isomer into another. 2 ̶ butene is a petrochemical which is produced by the catalytic cracking of crude oil. It is used in the production of gasoline and butadiene. It is a colorless liquefied petroleum gas.
- In $2 - butene$, the first and fourth carbon atoms form a covalent bond with three hydrogen atoms and one carbon atom. Thus in this position the carbon is $s{p^3}$ hybridized giving four hybrid orbital, forming four sigma bonds.
- The second and third carbon atoms have formed bonds with two hydrogen atoms and one carbon atom. Thus three sigma bonds are formed and the carbon atom is $s{p^2}$ hybridized. The Pz orbital from each central carbon atom undergo lateral overlap giving rise to a pi bond between second and third carbon atoms.
Thus the terminal carbon atom is $s{p^3}$ hybridized.
The correct answer is option “C” .

Note: Hybridization is the concept of mixing atomic orbitals into new hybrid orbitals. The intermixing is based on quantum mechanics. $s{p^2}$ hybridization is the mixing of one s orbital and two p atomic orbitals. $s{p^3}$ hybridization refers to the mixing of one s orbital and three p orbital to create hybrid orbitals. $s{p^2}$ hybrid orbitals have $33\%$ s orbital characteristics and $s{p^3}$ hybrid orbitals have $\;25\%$ s orbital characteristics.