When aqueous solutions of AgNO_3 and NaCl are mixed, a precipitate forms. Which compound is the precipitate?

• A. AgNO_3
• B. AgCl
• C. NaNO_3
• D. NaCl

Answer: (B)

Verified step by step guidance

1. Identify the ions present in the solutions before mixing: AgNO_3 dissociates into Ag^{+} and NO_3^{-} ions, and NaCl dissociates into Na^{+} and Cl^{-} ions.
2. When the two solutions are mixed, consider all possible combinations of cations and anions that can form new compounds: Ag^{+} can combine with Cl^{-} to form AgCl, and Na^{+} can combine with NO_3^{-} to form NaNO_3.
3. Recall the solubility rules: most nitrate (NO_3^{-}) salts and sodium (Na^{+}) salts are soluble in water, so NaNO_3 remains dissolved.
4. Silver chloride (AgCl) is known to be insoluble in water and will form a solid precipitate when Ag^{+} and Cl^{-} ions combine.
5. Therefore, the precipitate formed upon mixing AgNO_3 and NaCl solutions is AgCl.