Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion A : Benzene is more stable than hypothetical cyclohexatriene
Reason R : The delocalized electron cloud is attracted more strongly by nuclei of carbon atoms.
In the light of the above statements, choose the correct answer from the options given below:
Assertion A : Benzene is more stable than hypothetical cyclohexatriene
Reason R : The delocalized electron cloud is attracted more strongly by nuclei of carbon atoms.
In the light of the above statements, choose the correct answer from the options given below:
- A.A is false but R is true
- B.Both A and R are correct but R is NOT the correct explanation of A
- C.A is true but R is false
- D.Both A and R are correct and R is the correct explanation of A
Show answer and solution
Correct option: D
Solution
Benzene is more stable than hypothetical cyclohexatriene by about 150 kJ/mol — this extra stability is called resonance/delocalization energy, making Assertion A true. The reason for this extra stability is that the six π electrons are fully delocalized over all six carbon atoms, forming a continuous π cloud above and below the ring; this delocalized electron density is attracted more strongly (over a larger region) by the carbon nuclei compared to localized π bonds in cyclohexatriene, lowering the overall energy. Thus R correctly and directly explains A, making both statements true with R being the correct explanation of A.
[JEE Main 2023 · 24 Jan · Shift 2]