Question

The pair of electron in the given carbanion, $CH_3C \equiv$ $C^{-}$, is present in which of the following orbitals ?

• A. $sp^3$
• B. $sp^2$
• C. $sp$
• D. $2 p$

Answer 1

The Correct Option is C

 To determine in which orbital the pair of electrons in the carbanion \(CH_3C \equiv C^{-}\) is located, we need to analyze the hybridization state of the carbon atom that carries the negative charge.

1. First, identify the structure of the compound: \(CH_3C \equiv C^{-}\) consists of a methyl group \(CH_3\) bonded to a carbon atom, which is triple-bonded to another carbon, and this carbon carries the negative charge.
2. The carbon atom with the negative charge forms a triple bond with the adjacent carbon atom. When a carbon atom is involved in a triple bond, it is sp hybridized because:
   • Triple bonds consist of one sigma bond and two pi bonds.
   • The sigma bond arises from the overlap of sp hybrid orbitals.
   • The two pi bonds are formed by overlapping of p orbitals.
3. In the case of a carbanion like \(C^{-}\), the extra pair of electrons is found in the sp hybridized orbital. This is because hybridization affects the arrangement and type of orbitals available on the carbon atom.
4. Therefore, the pair of electrons is located in the \(sp\) orbital of the negatively charged carbon atom.

Thus, the correct answer is: \(sp\)

To rule out the other options:

• \(sp^3\): Typically found in saturated alkanes where carbon forms single bonds.
• \(sp^2\): Found in alkenes where carbon forms a double bond.
• \(2p\): Refers to a pure p orbital, not typically associated with hybridized states in carbanions.