Final answer:
Among the compounds listed, silver chloride (AgCl) is the insoluble one, due to the exception in the solubility rules which states that most chloride salts of silver are insoluble.
Step-by-step explanation:
Among the compounds listed, silver chloride (AgCl) is the insoluble one, due to the exception in the solubility rules which states that most chloride salts of silver are insoluble. The question pertains to the solubility of different compounds. According to solubility rules, most salts containing Group I elements like sodium and potassium are soluble, as well as salts containing nitrate ions.
However, certain salts are known to be insoluble, such as some silver, lead, and mercury salts. Specifically, silver chloride (AgCl) is insoluble. This is affirmed by the rule stating that while most chloride salts are soluble, those of silver, mercury, and lead are notable exceptions.
Consequently, in the list provided, sodium chloride (NaCl), potassium nitrate (KNO₃), and calcium sulfate (CaSO₄) are soluble, while silver chloride (AgCl) is insoluble. the compound that is insoluble is Silver chloride (AgCl). According to the solubility rules, chlorides are generally soluble, but those of Ag+, Pb²+, and Hg₂²+ are exceptions and are insoluble. Therefore, AgCl is the correct answer.