The number of sp² hybridized carbon in benzyne is

(1) 4

(2) 6

(3) 5

(4) 3

To determine the number of sp² hybridized carbon atoms in benzyne, we first need to understand the structure of benzyne itself. Benzyne is a derivative of benzene, characterized by a unique triple bond between two carbon atoms, which alters the hybridization of the surrounding carbon atoms.

Understanding Benzyne's Structure

Benzyne can be represented as a six-membered carbon ring, similar to benzene, but with a distinct feature: it has a triple bond between two of the carbon atoms. This triple bond results in a change in hybridization for those involved in the bond.

Hybridization Breakdown

In benzene, all six carbon atoms are sp² hybridized, meaning they each form three sigma bonds and have one unhybridized p orbital. However, in benzyne, the presence of the triple bond means that two of the carbon atoms are involved in this bond and are sp hybridized. The remaining four carbon atoms still retain their sp² hybridization.

Counting the Hybridized Carbons

• The two carbon atoms involved in the triple bond are sp hybridized.
• The other four carbon atoms in the ring remain sp² hybridized.

Thus, in benzyne, there are four sp² hybridized carbon atoms. Therefore, the correct answer to your question is:

(1) 4

Visualizing Benzyne

To visualize this, you might think of a standard benzene ring, where each vertex represents a carbon atom. When you introduce a triple bond between two of these vertices, those two carbons change their bonding characteristics, while the others maintain their original sp² configuration. This is a great example of how hybridization can change based on molecular structure and bonding.

In summary, benzyne has four sp² hybridized carbon atoms due to the presence of a triple bond between two of the carbon atoms, which alters their hybridization state. This understanding is crucial for grasping the behavior of aromatic compounds and their derivatives in organic chemistry.