Which of the following statements is correct for benzene ?

Options

A. All the six carbon atoms and all the six hydrogen atoms lie in different planes.
B. The ring system consists of three localised `C-C pi` -bonds.
C. The ring system consists of a delocalised `pi`-molecular orbital containing six electrons.
D. Each C atom is in a state of `sp^3` hybridisation.

Answer

To determine which statement is correct for benzene, we will analyze each option provided in the question step by step.

### Step 1: Analyze the first statement
**Statement 1:** All the six carbon atoms and all the six hydrogen atoms lie in different planes.

- **Analysis:** The structure of benzene is planar, meaning that all carbon and hydrogen atoms are in the same plane. Therefore, this statement is incorrect.

### Step 2: Analyze the second statement
**Statement 2:** The ring system consists of three localized C-C π bonds.

- **Analysis:** In benzene, the π bonds are not localized; they are delocalized across the ring. This means that the π electrons are shared among all six carbon atoms, creating a cloud of electron density above and below the plane of the ring. Hence, this statement is also incorrect.

### Step 3: Analyze the third statement
**Statement 3:** The ring system consists of a delocalized π molecular orbital containing 6 electrons.

- **Analysis:** This statement is correct. Benzene has a delocalized π system that includes six π electrons (two from each of the three double bonds). The delocalization contributes to the stability of the benzene molecule. Therefore, this statement is correct.

### Step 4: Analyze the fourth statement
**Statement 4:** Each carbon atom is in a state of sp³ hybridization.

- **Analysis:** In benzene, each carbon atom is bonded to three other atoms (two carbon atoms and one hydrogen atom) and has one unhybridized p orbital that participates in the delocalized π system. Therefore, each carbon atom is in a state of sp² hybridization, not sp³. This statement is incorrect.

### Conclusion
After analyzing all four statements, we find that the correct statement regarding benzene is:

**Correct Statement:** The ring system consists of a delocalized π molecular orbital containing 6 electrons.