The heat energy required to ionise the following molecules is given as follows
`N_(2)(g) overset(DeltaH_(1))to H_(2)^(o+)(g),O_(2)(g) overset(DeltaH_(2))to O_(2)^(+)(g)`
`Li_(2)(g) overset(DeltaH_(3)) to Li_(2)^(o+)(g),C_(2)(g) overset(DeltaH_(4))to C_(2)^(o+)(g)`
The correct decreasing order of energy in terms of heat

Options

A. `DeltaH_(1) gt DeltaH_(3) gt DeltaH_(2) gt DeltaH_(4)`
B. `DeltaH_(2) gt DeltaH_(3) gt DeltaH_(1) gt DeltaH_(4)`
C. `DeltaH_(3) gt DeltaH_(4)gt DeltaH_(1) gt DeltaH_(2)`
D. `DeltaH_(3) gt DeltaH_(1) gt DeltaH_(4) gt DeltaH_(2)`

Answer

C

Explanation

Enthalpy of ionisation depends upon the size of molecules. Larger the size lesser will be ionisation energy.