The most common type of reaction in aromatic compounds is

Which of the following is an example of an electrophilic substitution reaction?

At room temperature,styrene is in the ....... state.

Consider the following compounds/species:
The number of compounds/species which obey $H$ückel's rule is $..........$

For the following Friedel-Crafts alkylation reaction,which of the statements are correct?
$A$. Major product is n-propyl benzene.
$B$. iso-propyl carbocation intermediate is also generated.
$C$. Multiple substitution is inevitable.
$D$. Introducing electron-donating substituent on benzene will not produce any alkyl benzene.

$C_6H_6 + 3O_3$ $\longrightarrow X \stackrel{Zn / H_2O}{}$ ${\longrightarrow} Y$; $X$ and $Y$ are respectively