Hello!
The precipitate of the reaction that occurs when a silver nitrate solution is mixed with a sodium chloride solution is silver chloride (AgCl).
The chemical equation for this precipitation reaction is the following:
AgNO₃(aq) + NaCl(aq) → AgCl↓(s) + NaNO₃(aq)
Silver Chloride is a chemical compound that is poorly soluble in water because the chemical bond between Ag⁺ and Cl⁻ is very strong as the two ions are nearly the same size and have similar electronic densities. If the chemical bond is strong, it is more difficult for water molecules to break this bond to surround the individual ions, and thus solubility will decrease.
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