Solubility of Ionic Compounds in Water

Steps:

• Identify formulas: ammonium sulfate is (NH₄)₂SO₄; sodium carbonate is Na₂CO₃.
• Apply solubility rules: all ammonium salts are soluble; all sodium salts and group 1 carbonates are soluble.
• Confirm both dissolve readily in water at room temperature.
• Match to options: soluble for both indicates D.

Why D is correct:

• Solubility rules state ammonium and group 1 salts (including carbonates) are fully soluble, as exceptions do not apply here.

Why the others are wrong:

• A: Reverses actual solubilities; ammonium sulfate is soluble, not insoluble.
• B: Both are soluble, not insoluble.
• C: Reverses actual solubilities; sodium carbonate is soluble, not insoluble.

Final answer: D