Question

What do you mean by spectator ions? Give an example.

Answer 1

• Spectator ion: A spectator ion is one that does not participate in the chemical reaction; it is present both before and after the reaction takes place.
• Example: When a solution of sodium hydroxide (NaOH) is mixed with hydrochloric acid(HCl), the compounds dissociate into the ions ${\mathrm{Na}}^{+},{\mathrm{OH}}^{-},{\mathrm{H}}^{+}$and ${\mathrm{Cl}}^{-}$ .
• The hydrogen and hydroxide ions react to form water, but the sodium and chlorine ions stay in solution unchanged.
• Hence, they are called spectator ions because they are present but only "watching" as the precipitate form.