Effect on acidity of benzene due to electron withdrawing groups With respect to the compounds I–V, choose the correct statement(s).


Compound II becomes more acidic when it has a $\ce{-NO2}$ substituent.
The acidity of compounds follows the order I &gt; IV &gt; V &gt; II &gt; III.
The conjugate base of compound IV is aromatic.
The acidity of compound I is due to delocalization in the conjugate base.


I am not able to decide about the first statement properly. I compared the acidity by considering the conjugate base, which is the same (benzyne) even if $\ce{NO2}$ group is added.
However, the solution says that it will increase acidity because of being an electron withdrawing group.
Both the predictions are good. The $\ce{NO2}$ will actually be an effective electron withdrawing group, and the lost of that $\ce{H}$ will stabilize the compound (if there is and $\ce{NO2}$ on it). It is also important to rescue, that both effects will be stronger just on para or ortho position. You can make the different structures to check it.