The enthalpy of hydrogenation of cyclohexene is `-119.5KJ` . If resonance energy of benzene is `-150.4KJMol^(-1)` , its enthalpy of hydrogenation of benzene would be

Options

A. `-269.9kJ mol^(-1)`
B. ` -358.5kJ mol^(-1)`
C. ` -508.9 kJ mol^(-1)`
D. ` - 208.1 kJ mol^(-1)`

Answer

d

Explanation

Enthalpy of hydrogenation of cyclohexene

`:.`Calculated enthalpy of hydrogenation of benzene.

`= - 385.5 kJmol^(-1)`
As actual value is lower by amount equal to resonance energy , therefore,actual enthalpy of hydrogenation
` = - 385.5kJ mol^(-1) - ( - 150 .4kJ mol^(-1))`
`= - 208.1kJ mol^(-1)`