Question:
The enthalpy of combustion of cyclohexane, cyclohexene and \(\text{H}_2\) are respectively \(-3920,-3800\) and \(-241\) KJ mol\(^{-1}\). The enthalpy of hydrogenation of cyclohexene is
The enthalpy of combustion of cyclohexane, cyclohexene and \(\text{H}_2\) are respectively \(-3920,-3800\) and \(-241\) KJ mol\(^{-1}\). The enthalpy of hydrogenation of cyclohexene is
Show Hint
Use Hess law: hydrogenation = combustion of reactants minus combustion of product.
Updated On: Oct 1, 2026
- \(-121\) KJ mol\(^{-1}\)
- \(+121\) KJ mol\(^{-1}\)
- \(-242\) KJ mol\(^{-1}\)
- \(+242\) KJ mol\(^{-1}\)
Show Solution
Verified By Collegedunia
The Correct Option is A
Solution and Explanation
Step 1: Reaction
Cyclohexene \(+\text{H}_2\to\) cyclohexane.
Step 2: Hess law
\(\Delta H_{hyd}=\Delta H_c(\text{cyclohexene})+\Delta H_c(\text{H}_2)-\Delta H_c(\text{cyclohexane})\).
\[ =-3800-241-(-3920)=-121\text{ kJ mol}^{-1} \]
Step 3: Result
Option (A).
Final Answer:
\(\Delta H_{hyd}=-121\) kJ mol\(^{-1}\), option (A). \[ \boxed{\text{(A)}} \]
Cyclohexene \(+\text{H}_2\to\) cyclohexane.
Step 2: Hess law
\(\Delta H_{hyd}=\Delta H_c(\text{cyclohexene})+\Delta H_c(\text{H}_2)-\Delta H_c(\text{cyclohexane})\).
\[ =-3800-241-(-3920)=-121\text{ kJ mol}^{-1} \]
Step 3: Result
Option (A).
Final Answer:
\(\Delta H_{hyd}=-121\) kJ mol\(^{-1}\), option (A). \[ \boxed{\text{(A)}} \]
Was this answer helpful?
0
0
Top MHT CET Chemistry Questions
- The temperature of $32^{\circ}C$ is equivalent to
- The heat of formation of water is $ 260\, kJ $ . How much $ H_2O $ is decomposed by $ 130\, kJ $ of heat ?
- If a metal crystallises in bcc structure with edge length of unit cell $4.29 \times 10^{-8}\, cm$ the radius of metal atom is
- Which of the following oxides can act both as an oxidising agent as well as reducing agent ?
- "The mass and energy both are conserved in an isolated system", is the statement of
View More Questions
Top MHT CET Thermochemistry Questions
- For the reaction,
\[ C_2H_5OH(l) + 3O_2(g) \rightarrow 2CO_2(g) + 3H_2O(l) \] Which among the following is true?
- Identify the side chain –R present in amino acid lysine.
- Heat of combustion of liquid benzene to carbon dioxide and water is \(-3266 \, \text{kJ/mol}\). What is the amount of heat liberated when 780 mg of benzene is fully oxidised? (At mass of C = 12, H = 1)
From the given reaction,
\(\mathrm{N_2(g) + 3H_2(g) \rightarrow 2NH_3(g)},\ \Delta H = -92.6\,\text{kJ}, the enthalpy of formation of \mathrm{NH_3} is\)Standard enthalpy of formation of water is \(-286\,\text{kJ mol}^{-1}\). When \( 1800\,\text{mg}\) of water is formed from its constituent elements in their standard states, the amount of energy liberated is
View More Questions
Top MHT CET Questions
- During r- DNA technology, which one of the following enzymes is used for cleaving DNA molecule ?
- In non uniform circular motion, the ratio of tangential to radial acceleration is (r = radius of circle, $v =$ speed of the particle, $\alpha =$ angular acceleration)
- The temperature of $32^{\circ}C$ is equivalent to
- The line $5x + y - 1 = 0$ coincides with one of the lines given by $5x^2 + xy - kx - 2y + 2 = 0 $ then the value of k is
- The heat of formation of water is $ 260\, kJ $ . How much $ H_2O $ is decomposed by $ 130\, kJ $ of heat ?
View More Questions