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MHT CET202519 Apr 2025Evening ShiftChemistryThermodynamics (C)Actual

Calculate the enthalpy change of vaporisation of benzene if 13 gram of benzene vaporised by supplying 5.1 kJ of heat.

Options

  1. A43 5 ~kJ ~mol ⁻¹
  2. B35 3 ~kJ ~mol ⁻¹
  3. C30 6 ~kJ ~mol ⁻¹
  4. D40 7 ~kJ ~mol ⁻¹

Correct answer

C. 30 6 ~kJ ~mol ⁻¹

Step-by-step solution

Enthalpy change of vaporisation calculation for benzene The molar mass of benzene (C₆H₆) is 6 12 + 6 1 = 78 g/mol. With 13 g vaporized, the number of moles is 13 78 = 1 6 mol. Given that 5.1 kJ of heat is supplied, the enthalpy change per mole is calculated as H_ vap = 5.1 1/6 = 5.1 6 = 30.6 kJ/mol. The calculated value of 30.6 kJ/mol corresponds to option C. Final answer: C

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