Write an equation that represents the action in water of nitrous acid as an arrhenius acid.

Arrhenius Acid:
                       Arrhenius Acid is any specie which when dissolved in water produces H⁺ (proton) Ions.

Nitrous Acid:
                    Nitrous Acid also acts as Arrhenius Acid when dissolved in water.

                          HNO₂  +  H₂O    →    NO₂⁻  +  H₃O⁺
Where,
                                H₃O⁺    ⇆    H⁺  +  H₂O

As HNO₂ produces H⁺ Ions in water, so it is an Arrhenius Acid.

The density would be 1.622