nitro group is a strong withdrawing group and deactivating also so the positive charge on the benzene increases....if the positive charge increases the acidic nature increases.... therefore nitrobenzene is more acidic than benzene....

Which nitrobenzene is most acidic?

NO2 group at o and p position withdraws electron of o-h bond towards it by stronger M-effect while the NO2 group at m position withdraws electron of o-h bond by weaker I -effect . Thus o and p are nitrophenols are more acidic than m-nitrophenol.

What is the nature of nitrobenzene?

Nitrobenzene is an industrial chemical. It is an oily yellow liquid with an almond-like odor. It dissolves only slightly in water and will evaporate to air.