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MHT CET202013 Oct 2020Morning ShiftChemistryThermodynamics (C)Actual

Average bond enthalpy of water is 464 5 ~kJ ~mol ⁻¹ . If the energy required to break first 0- H bond is 502 ~kJ ~mol ⁻¹ , how much energy per mol is required to break second 0 -H bond?

Options

  1. A929 ~kJ
  2. B251 ~kJ
  3. C427 ~kJ
  4. D678 ~kJ

Correct answer

C. 427 ~kJ

Step-by-step solution

Average bond enthalpy of H ₂ O is 464.5 ~kJ ~mol ⁻¹ array ll H ₂ O _ (z) H _ (z) + OH _ (z) & H ₁=502 ~kJ ~mol ⁻¹ OH _ (z) H _ (z) + O _ (g) & H ₂=? array Average bond enthalpy = H ₁+ H ₂ 2 464.5 2=502+ H ₂ H ₂=929-502=427 ~kJ ~mol ⁻¹

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