Resonance in $\text{X}_2\text{Y}$ can be represented as 
The enthalpy of formation of $\text{X}_2\text{Y} \left( \text{X}\equiv\text{X (g)} + \frac{1}{2}\text{Y}=\text{Y (g)} \rightarrow \text{X}_2\text{Y (g)} \right)$ is $80 \text{ kJ mol}^{-1}$. The magnitude of resonance energy of $\text{X}_2\text{Y}$ is _______ $\text{kJ mol}^{-1}$.(Nearest integer value)
[Given : Bond energy of $\text{X}\equiv\text{X}$, $\text{X}=\text{X}$, $\text{Y}=\text{Y}$ and $\text{X}=\text{Y}$ are $940$, $410$, $500$ and $602 \text{ kJ mol}^{-1}$ respectively. Valence X : 3, Y : 2]
