Which of the following statement is/are correct about benzene

Options

A. It burns with scooty flame
B. It undergoes electrophilic substitution reaction
C. Its resonace energy is `36 kcal mol^(-1)`
D. It is highly unsaturated and decolourises bromine water

Explanation

To determine which statements about benzene are correct, we will analyze each statement one by one.

1. **Benzene as an Aromatic Compound**:
Benzene (C6H6) is indeed an aromatic compound. It has a cyclic structure and follows Huckel's rule, which states that a compound must have (4n + 2) π electrons to be aromatic. Benzene has 6 π electrons (n=1), confirming its aromaticity.

2. **Cyclic Compound**:
Benzene is a cyclic compound, consisting of six carbon atoms arranged in a ring, with alternating double bonds. This cyclic structure is essential for its aromatic properties.

3. **Hybridization**:
All carbon atoms in benzene are sp² hybridized. Each carbon atom forms three sigma bonds (two with adjacent carbon atoms and one with a hydrogen atom) and has one unhybridized p orbital that contributes to the delocalized π system.

4. **Burning with Sooty Flame**:
Benzene does burn with a sooty flame due to its high carbon content and the incomplete combustion of hydrocarbons, which produces soot.

5. **Electrophilic Substitution Reaction**:
Benzene undergoes electrophilic substitution reactions rather than addition reactions, which is a characteristic behavior of aromatic compounds. This is because the aromatic system is stable and prefers to retain its aromaticity.

6. **Resonance Energy**:
The resonance energy of benzene is approximately 36 kcal/mol. This energy is a measure of the stability that resonance provides to the molecule.

7. **Highly Unsaturated**:
Benzene is considered highly unsaturated due to the presence of multiple π bonds. However, it is not "unsaturated" in the same way as alkenes or alkynes because it does not readily undergo addition reactions.

8. **Decolorization of Bromine Water**:
Benzene does not decolorize bromine water under normal conditions because it does not readily react with bromine in the absence of a catalyst. This is a key distinction from alkenes, which do react with bromine.

9. **Degree of Unsaturation**:
Benzene has a degree of unsaturation of 4, calculated using the formula (2C + 2 - H)/2. For benzene, (2(6) + 2 - 6)/2 = 4.

### Summary of Statements:
- **Option 1**: Correct (Benzene burns with a sooty flame)
- **Option 2**: Correct (Benzene undergoes electrophilic substitution and has a resonance energy of 36 kcal/mol)
- **Option 3**: Incorrect (Benzene does not decolorize bromine water)

### Final Answer:
- The correct statements about benzene are:
- It burns with a sooty flame.
- It undergoes electrophilic substitution reaction.
- Its resonance energy is 36 kcal/mol.
- It is highly unsaturated and has a degree of unsaturation of 4.