Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
MHT CET202617 April 2026Morning ShiftChemistryThermodynamics (C)Actual

At 25 ^ C standard enthalpy of combustion of H ₂ , Cyclohexene and cyclohexane are -241, -3800 and -3920 kJ mol ⁻¹ respectively. What is the heat of hydrogenation of cyclohexene?

Options

  1. A-121 kJ
  2. B-242 kJ
  3. C121 kJ
  4. D363 kJ

Correct answer

A. -121 kJ

Step-by-step solution

The hydrogenation reaction of cyclohexene is given by: C ₆ H ₁₀ + H ₂ C ₆ H ₁₂ The enthalpy of hydrogenation can be calculated using the standard enthalpies of combustion of the reactants and products: H = H_c( Reactants ) - H_c( Products ) H = H_c( C ₆ H ₁₀) + H_c( H ₂) - H_c( C ₆ H ₁₂) Substituting the given values: H = -3800 + (-241) - (-3920) H = -4041 + 3920 = -121 kJ mol ⁻¹ Answer: -121 kJ

Practice Thermodynamics (C) on Quantrex Academy →

More from Thermodynamics (C)

Identify the INCORRECT statement 2026The standard enthalpies of formation of CH₄ (g), CO₂ (g) and H₂ O(l) are -74.8 kJ mol ⁻¹ , -393.5 kJ mol ⁻¹ and -285.8 kJ mol ⁻¹ respectively. Then the enthalpy change for the give 2026For an ideal gas undergoing an isothermal change, there is 2026Ozone is formed by the reaction O _ 2(g) + O _ (g) O _ 3(g) , H = -107.2 kJ . Given O=O bond energy is 498.0 kJ mol ⁻¹ , the average bond energy of ozone is: 2026H and S for a reaction are 35.5 kJ mol ⁻¹ and 83.6 J K ⁻¹ respectively. Assuming that H and S do not vary with temperature, the reaction is spontaneous when: 2026The heat of combustion of carbon to CO ₂ is -393.5 kJ mol ⁻¹ . The heat released on the formation of 35.2 g of CO ₂ by combustion of C is: 20265 moles of a gas is allowed to pass through a series of changes as shown in the graph, in a cyclic process. The processes C A , B C and A B respectively are 20251 mole of an ideal gas is allowed to expand isothermally and reversibly from 1 L to 5 L at 300 K. The change in enthalpy (in kJ ) is ( R =8.3 ~J ~K ⁻¹ ~mol ⁻¹ ) 2025 Full Thermodynamics (C) list All MHT CET PYQs