Which of the following substances is most likely to be more soluble in 1.0 M HCl than in 1.0 M NaOH?

• A. KNO3
• B. CaCO3
• C. NaCl
• D. BaSO4

Answer: (B)

Verified step by step guidance

1. Understand the nature of the substances and the solvents: 1.0 M HCl is a strong acid, and 1.0 M NaOH is a strong base. The solubility of substances can depend on their chemical behavior in acidic or basic environments.
2. Identify the chemical properties of each substance: KNO3 and NaCl are salts of strong acids and strong bases, so their solubility is generally not affected significantly by acidic or basic conditions. BaSO4 and CaCO3 are salts that can react with acids or bases.
3. Focus on CaCO3, which is calcium carbonate. It is known to be sparingly soluble in water but reacts with acids to form soluble calcium ions and carbon dioxide gas, increasing its solubility in acidic solutions like 1.0 M HCl.
4. Write the reaction of CaCO3 with HCl: \(\mathrm{CaCO_3 (s) + 2HCl (aq) \rightarrow Ca^{2+} (aq) + 2Cl^- (aq) + CO_2 (g) + H_2O (l)}\). This reaction shows that CaCO3 dissolves better in acid due to the formation of soluble products and gas evolution.
5. In contrast, in 1.0 M NaOH, CaCO3 does not react significantly to increase solubility, so it remains less soluble. Therefore, CaCO3 is more soluble in 1.0 M HCl than in 1.0 M NaOH.