$A$ species having carbon with a sextet of electrons and which can act as an electrophile is called:

The correct stability order for the following species is:
$(I)$ $o-CN-C_6H_4-CH_2^-$
$(II)$ $m-CN-C_6H_4-CH_2^-$
$(III)$ $p-CN-C_6H_4-CH_2^-$
$(IV)$ $C_6H_5-CH_2^-$
(Note: The image shows the structures of these carbanions.)

The correct order of stability is:

Which of the following species is a radical?

Which carbocation is the least stable?

Which one of the following is an electrophilic intermediate in the reaction of benzene with $CH_3Cl$ in the presence of anhydrous $AlCl_3$?