Table of contents

1. Intro to General Chemistry3h 48m
2. Atoms & Elements4h 16m
3. Chemical Reactions4h 10m
4. BONUS: Lab Techniques and Procedures1h 38m
5. BONUS: Mathematical Operations and Functions48m
6. Chemical Quantities & Aqueous Reactions3h 53m
7. Gases3h 49m
8. Thermochemistry2h 37m
9. Quantum Mechanics2h 58m
10. Periodic Properties of the Elements3h 9m
11. Bonding & Molecular Structure3h 29m
12. Molecular Shapes & Valence Bond Theory1h 57m
13. Liquids, Solids & Intermolecular Forces2h 23m
14. Solutions3h 1m
15. Chemical Kinetics2h 53m
16. Chemical Equilibrium2h 29m
17. Acid and Base Equilibrium5h 1m
18. Aqueous Equilibrium4h 47m
19. Chemical Thermodynamics1h 50m
20. Electrochemistry2h 42m
21. Nuclear Chemistry2h 36m
22. Organic Chemistry5h 7m
23. Chemistry of the Nonmetals2h 39m
24. Transition Metals and Coordination Compounds3h 16m

6. Chemical Quantities & Aqueous Reactions

Solubility Rules

General Chemistry

6. Chemical Quantities & Aqueous Reactions

Solubility Rules

Previous problemNext problem

Struggling with General Chemistry?

Join thousands of students who trust us to help them ace their exams!Watch the first video

Multiple Choice

For which of the following aqueous solutions will a decrease in pH increase the solubility of the compound?

BaSO4

NaCl

CaCO3

KNO3

Previous problemNext problem

Verified step by step guidance

Step 1: Understand that the solubility of a compound in water can be affected by pH if the compound contains an anion that can react with H\_3O\^+ (or H\^+). This typically applies to salts containing basic anions that can be protonated, such as carbonate (CO\_3\^{2-}), sulfide (S\^{2-}), or phosphate (PO\_4\^{3-}).

Step 2: Analyze each compound's anion to see if it can react with H\^+ ions. For BaSO\_4, the anion is sulfate (SO\_4\^{2-}), which is the conjugate base of a strong acid (H\_2SO\_4), so it does not react significantly with H\^+. For NaCl and KNO\_3, the anions are chloride (Cl\^-) and nitrate (NO\_3\^-), both conjugate bases of strong acids and do not react with H\^+.

Step 3: For CaCO\_3, the anion is carbonate (CO\_3\^{2-}), which is a base and can react with H\^+ to form bicarbonate (HCO\_3\^-) and carbonic acid (H\_2CO\_3). This reaction reduces the concentration of CO\_3\^{2-} in solution, shifting the dissolution equilibrium to dissolve more CaCO\_3, thus increasing its solubility as pH decreases.

Step 4: Write the dissolution equilibrium for CaCO\_3: $\mathrm{CaCO\_3 (s) \rightleftharpoons Ca^{2+} (aq) + CO\_3^{2-} (aq)}$ and the protonation reaction: $\mathrm{CO\_3^{2-} + H^+ \rightleftharpoons HCO\_3^-}$. The removal of CO\_3\^{2-} by protonation shifts the equilibrium to the right, increasing solubility.

Step 5: Conclude that only compounds with anions that can be protonated (like carbonate in CaCO\_3) will have increased solubility with decreasing pH, while salts like BaSO\_4, NaCl, and KNO\_3 will not show this effect.