Question

In the given reaction

Fig. 

the number of sp² hybridised carbon(s) in compound ‘X’ is _____.

Answer 1

Correct Answer: 8

The reaction involves multiple steps to determine the structure of compound ‘X’ and count the number of sp² hybridised carbons.

Step 1: Oxidation
The starting molecule is cyclohexanol. In the presence of K₂Cr₂O₇/H⁺, the alcohol group is oxidised to a ketone, forming cyclohexanone.

Step 2: Grignard Reaction
Cyclohexanone reacts with C₆H₅MgBr (a Grignard reagent) to form an alcohol. This step involves the addition of the phenyl group, resulting in 1-phenylcyclohexanol.

Step 3: Dehydration
Under acidic conditions and heat, dehydration occurs, forming an alkene. The major product formed has the double bond conjugated with the phenyl group, due to greater stability.

Final Structure of 'X'
The resulting product is 1-phenylcyclohexene, where the phenyl and the newly formed alkene contribute to the number of sp² hybridised carbons.

Counting sp² Hybridised Carbons
1-Phenylcyclohexene has:
- 6 sp² carbons in the phenyl group.
- 2 sp² carbons in the cyclohexene ring.

Total sp² Hybridised Carbons in 'X'
The total number of sp² hybridised carbons is 8.

Verification
The count of sp² hybridised carbons (8) matches the expected range (8-8).