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MHT CET202210 Aug 2022Morning ShiftChemistryThermodynamics (C)Actual

The bond enthalpies of C - C , C = C , H - H and C - H bonds are 360,600,400 and 410 ~kJ ~mol ⁻¹ respectively. What is the heat of hydrogenation of ethylene?

Options

  1. A-450 ~kJ ~mol ⁻¹
  2. B-260 ~kJ ~mol ⁻¹
  3. C-180 ~kJ ~mol ⁻¹
  4. D-400 ~kJ ~mol ⁻¹

Correct answer

C. -180 ~kJ ~mol ⁻¹

Step-by-step solution

aligned H & = B E _ in - B E _ out & = ( B E _ C = C +4 ~B E _ C - H + B E _ H - H )- ( B E _ C - C +6 ~B E _ C - H ) & = B E _ C = C + B E _ H - H - B E _ C - C -2 ~B E _ C - H & =600+400-360-2 410=-180 ~kJ aligned

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