Answer:
[tex]Ka=\frac{[NO_{2}^{-}][H_{3}O^{+} ]}{[HNO_{2}]}[/tex]
Explanation:
Let's consider the acid dissociation of nitrous acid in water.
HNO₂(aq) + H₂O(l) ⇄ NO₂⁻(aq) + H₃O⁺(aq)
The acid dissociation constant (Ka) is the product of the concentration of the products raised to their stoichiometric coefficients divided by the product of the concentrations of the reactants raised to their stoichiometric coefficients. It does not include solids or pure liquids (H₂O(l) in this case).
[tex]Ka=\frac{[NO_{2}^{-}][H_{3}O^{+} ]}{[HNO_{2}]}[/tex]