Resonance energy:

The energy differecnce between most stable resonating structure and resonance hybrid is known as

resonance energy.

 (1) It ís the experimental value which is calculated by heat of hydrogenation (HOH).

(2) Higher the value of resonance energy, greater is the resonance stabilization.

Resonance Energy of Benzene :

The experimental value heat of hydrogenation for benzene is 51 Kcal.

The resonance energy of benzene is calculated fromthe heat of hydrogenation as given below :

Resonance energy comparison:

(1) Consider better resonance or equivalent resonating structures,molecules having equivalent resonating

structures must have more resonance energy, than non-equivalent resonating structures.

(2) Aromatic compound have more resonance energythan non-aromatic compound. 

(3) In case of larger conjugation, more will be the Resonance energy.

(4) Resonance energy will be more, when π-bond, lone pair conjugation is present than π, π-conjugation

Related questions;

(1) What is Steric Inhibition in Resonance of SIR effect ?

(2) What is the Inversion of Amines ?

(4) Which is more stable? CH3-CH2+ (Ethyl carbocation) or CH2=CH+ (Vinyl carbocation)? And why?

(5) Why The phenoxide ion is more stable than phenol ?

(6) What happens if two deactivating and one activating group is present on a benzene ring?

(7) Among orthochlorophenol and orthofluorophenol, which will be a stronger acid and why?

(8) Why benzyl carbonium ion is more stable than ethyl carbonium ion?

(9) Explain why aniline is less basic than ammonia?

(10) 4- nitrophenol is more acidic than 3,5 - dimethyl –4-nitro-phenol. Explain.

(11) What are the difference between Tautomerism & Resonance ?

(12) Though enol form is less stable than keto form, phenol exists in enol form, why?

(13) What is the nucleophilicity of halides?

(14) What is correct acidic strengths order of the haloforms acids ? Give correct explanation.

(15) Why are bridge head carbocations unstable?

(16) Why is cyclopropyl methyl carbocation exceptionally stable?

(17) Azabicyclo[2,2,1]heptane is more basic thantriethylamine why?.

(18) Which carbocation is more stable : Benzyl or Tertiary?

(18) Which is more stable ,vinyl carbocation or allyl carbocation?

(19) Which carbocation is more stable : Benzyl or Tertiary?

(20) Although both in benzylic carbanion and cyclopentadienyl anion 6 electrons are spread, but benzylic carbanion is more stable. Why?