Solubility rules for metal salts

Steps:

• Carbonates are insoluble except for Group 1 metals like potassium.
• Chlorides are soluble except for silver, lead, and mercury(I).
• Sulfates are soluble except for barium, strontium, lead, and calcium.
• Only potassium has all three salts soluble.

Why C is correct:

• Potassium, a Group 1 metal, forms K2CO3, KCl, and K2SO4, all highly soluble per solubility rules for alkali metal compounds.

Why the others are wrong:

• A. Barium sulfate (BaSO4) is insoluble.
• B. Calcium carbonate (CaCO3) is insoluble.
• D. Silver chloride (AgCl) is insoluble.

Final answer: C