Standard enthalpy of formation of gaseous ethane, ethene and benzene from gaseous atoms are -2828, -2258 and -5518 kJ/mol, respectively. The bond enthalpy of C-H bond is 416 kJ/mol. The magnitude of r

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Standard enthalpy of formation of gaseous ethane, ethene and benzene from gaseous atoms are -2828, -2258 and -5518 kJ/mol, respectively. The bond enthalpy of C-H bond is 416 kJ/mol. The magnitude of resonance energy of benzene, compared with one Kekulé structure is

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Ethane (6 C-H + C-C): BE(C-C) = 2828 - 6(416) = 332 kJ/mol. Ethene (4 C-H + C=C): BE(C=C) = 2258 - 4(416) = 594 kJ/mol. One Kekulé benzene: 6(416) + 3(332) + 3(594) = 2496 + 996 + 1782 = 5274 kJ/mol. Resonance energy = 5518 - 5274 = 244 kJ. This is option (d).

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