Solubility Rules for Common Anions in Salts

Steps:

• Recall solubility rules: salts with certain anions dissolve fully in water regardless of cation.
• Examine carbonates (CO3^2-): insoluble except with alkali metals or ammonium.
• Examine chlorides (Cl-): soluble except with Ag+, Pb2+, Hg2^2+.
• Examine nitrates (NO3-): always soluble with any cation.
• Examine sulfates (SO4^2-): soluble except with Ba2+, Sr2+, Pb2+, Ca2+ (slightly).

Why C is correct:

• Nitrates (NO3-) form soluble salts with all cations, per standard solubility guidelines, as no exceptions exist.

Why the others are wrong:

• A. Carbonates insoluble with most cations, like CaCO3.
• B. Chlorides form insoluble salts with Ag+, Pb2+, Hg2^2+ (e.g., AgCl).
• D. Sulfates insoluble with Ba2+, Pb2+ (e.g., BaSO4).

Final answer: C