Heats of hydrogenation (to cyclohexane) : cyclohexene -120 kJ/mol, cyclohexa-1,4-diene -240 kJ/mol, cyclohexa-1,3-diene -232 kJ/mol, benzene -208 kJ/mol.
Calculate ΔH (kJ/mol, with sign) for cyclohexa-1,3-diene $\to$ cyclohexa-1,4-diene.

Question

Heats of hydrogenation (to cyclohexane) : cyclohexene -120 kJ/mol, cyclohexa-1,4-diene -240 kJ/mol, cyclohexa-1,3-diene -232 kJ/mol, benzene -208 kJ/mol.

Calculate ΔH (kJ/mol, with sign) for cyclohexa-1,3-diene $\to$ cyclohexa-1,4-diene.

TestHub · Accepted Answer

Cyclohexa-1,3-diene → cyclohexane is -232 kJ/mol and cyclohexa-1,4-diene → cyclohexane is -240 kJ/mol. ΔH = -232 - (-240) = +8 kJ/mol.

Chemistry - GOC Question with Solution | TestHub

Doubts & Discussion