= Solution
\b[Bulk <electroneutrality> gives $\boxed{[\mathrm{NO_3^-}]=[\mathrm{H^+}]+2[\mathrm{Zn^{2+}}]}$.] Each dissolved <zinc> ion contributes two positive elementary charges, whereas each nitrate contributes one negative charge.
This assumes complete <nitric acid> dissociation, only $\mathrm H^+$ and $\mathrm{Zn^{2+}}$ as significant cations, and only nitrate as a significant anion. It neglects $\mathrm{OH^-}$ at acidic <pH>, other dissolved salts, zinc complexes and additional ionic nitrogen products. It is a bulk charge balance; a thin charged electrode interface does not invalidate bulk electroneutrality.
Back to article page
