Question

Explain why Silver nitrate crystals are dissolved in distilled water and not in tap water to prepare silver nitrate solution as a laboratory reagent.

Answer 1

• Tap water, river water, and well water contain dissolved solids such as Sodium chloride, minerals, and impurities but distilled water does not contain any dissolved solids.
• When we mix Silver nitrate$\left({\mathrm{AgNO}}_3\right)$ crystals in tap water then it reacts with the Sodium chloride$\left(\mathrm{NaCl}\right)$ present in it and forms a white color precipitate of Silver chloride$\left(\mathrm{AgCl}\right)$.
• $\underset{\mathrm{Nitrate}}{\underset{\mathrm{Silver}}{{\mathrm{AgNO}}_3\left(\mathrm{aq}\right)}}+\underset{\mathrm{Chloride}}{\underset{\mathrm{Sodium}}{\mathrm{NaCl}\left(\mathrm{aq}\right)}}\to \underset{\mathrm{Chloride}}{\underset{\mathrm{Silver}}{\mathrm{AgCl}\left(\mathrm{s}\right)}}+\underset{\mathrm{Nitrate}}{\underset{\mathrm{Sodium}}{{\mathrm{NaNO}}_3\left(\mathrm{aq}\right)}}$
• We always mix Silver nitrate crystals in distilled water to form silver nitrate solution as a laboratory reagent as it does not have any dissolved salts.