How to draw molecular orbital diagrams for protonated/deprotonated methyl red?


> 
> Give a molecular structure-based explanation for the differences in the UV-Vis
> spectra in **I** and **II**. Use detailed MO schemes for **A** and **B** for illustration. (12 marks)
> 
> 
> [![Methyl red protonation](https://i.stack.imgur.com/RjOFE.png)](https://i.stack.imgur.com/RjOFE.png)
> 
> 
> 


Does the double bond of N=N, C=O and lone pair of oxygen and nitrogen involved in the MO diagram?


