Which of the following will be easily nitrated?

The major product obtained in the given reaction 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.

Draw the structure of the compound having molecular formula $C_7H_8$ and determine the number of $\sigma$ and $\pi$ bonds.

What do you mean by ortho and para directing groups? Explain the ortho and para directing effect by taking the example of any group.

Cyclopentadiene is much more acidic than cyclopentane. The reason is that