Statement 1 : The crystal structures of ${\mathrm{NaHCO}}_3\mathrm{and}{\mathrm{KHCO}}_3$ both show intermolecular hydrogen bonding but are different.

Statement 2 : In ${\mathrm{NaHCO}}_3\mathrm{and}{\mathrm{HCO}}_3^{-}$ ions are linked together through intermolecular hydrogen bonds into an infinite chain, while in ${\mathrm{KHCO}}_3,{\mathrm{HCO}}_3^{-}$ ions form dimeric anions through intermolecular hydrogen bonds.

Nitration of Benzene

When benzene is treated with a mixture of concentrated nitric acid and concentrated sulfuric acid (nitrating mixture), a nitro group (−NO2) is introduced into the benzene ring to form nitrobenzene.

Reaction:

C₆H₆ + HNO₃ → C₆H₅NO₂ + H₂O (in presence of H₂SO₄)

Stepwise Mechanism:

Generation of Electrophile:
HNO₃ + H₂SO₄ → NO₂⁺ + HSO₄^- + H₂O

Attack on Benzene
The nitronium ion (NO₂⁺) attacks the benzene ring to form an arenium ion (intermediate).

Restoration of Aromaticity:
The intermediate loses H⁺, giving nitrobenzene (C₆H₅NO₂).

Final Product: Nitrobenzene (C₆H₅NO₂)

By-product: Water (H₂O)