$TNT$ has the structure

Identify the meta-directing group from the following.

What is the expected order of reactivity of the following compounds in electrophilic chlorination $(Cl_2 + FeCl_3)$? (more reactive $ > $ less reactive)
$I: C_6H_5CH_2CO_2H$
$II: C_6H_5N(CH_3)_2$
$III: C_6H_5OCOCH_3$
$IV: C_6H_5CCl_3$

When acetylene is passed through a red hot iron tube,compound $X$ is formed. Which one of the following reactions will yield $X$ as the major product?

Which one of the following functional groups is not meta directing?

The number of $\pi$ electrons in the following molecule is: