If enthalpy change for hydrogenation of ethylene is − 132 kJ / mole and enthalpy of formation 1,3-butadiene (g) and butane (g) are 115 kJ and − 140 kJ / mole respectively then calculate the magnitude

Question

If enthalpy change for hydrogenation of ethylene is − 132 kJ / mole and enthalpy of formation 1,3-butadiene (g) and butane (g) are 115 kJ and − 140 kJ / mole respectively then calculate the magnitude of resonance energy of 1,3-butadiene (in kJ).

TestHub · Accepted Answer

Concepts: Resonance energy, enthalpy of hydrogenation, enthalpy of formation.

Resonance Energy = Expected $Δ H_{h y d ro g e na t i o n}$ - Observed $Δ H_{h y d ro g e na t i o n}$

Expected $Δ H = 2 \times (- 132) = - 264$ kJ/mol

Observed $Δ H = Δ H_{f} (C_{4} H_{10}) - Δ H_{f} (C_{4} H_{6}) = - 140 - 115 = - 255$ kJ/mol

Resonance Energy $= - 264 - (- 255) = - 9$ kJ/mol

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JEE Main (2028)