Textbook Question
Use Le Châtelier's principle to predict whether the solubility of BaF2 will increase, decrease, or remain the same on addition of each of the following substances. (d) Ba1NO322
Ch.17 - Applications of Aqueous Equilibria
Chapter 17, Problem 113
Which of the following compounds are more soluble in an acidic solution than in pure water? Write a balanced net ionic equation for each dissolution reaction: (b) CaCO3, (c) Ni(OH)2, (d) Ca3(PO4)2.
Verified step by step guidance1
Identify the compounds that are more soluble in acidic solutions. Compounds that contain anions which can react with H+ ions from the acid will be more soluble in acidic solutions.
For CaCO3, recognize that the carbonate ion (CO3^2-) can react with H+ to form H2CO3, which decomposes to CO2 and H2O. Write the net ionic equation: CaCO3(s) + 2H+(aq) -> Ca^2+(aq) + CO2(g) + H2O(l).
For Ni(OH)2, note that the hydroxide ion (OH^-) can react with H+ to form water. Write the net ionic equation: Ni(OH)2(s) + 2H+(aq) -> Ni^2+(aq) + 2H2O(l).
For Ca3(PO4)2, consider that the phosphate ion (PO4^3-) can react with H+ to form HPO4^2- or H2PO4^-. Write the net ionic equation: Ca3(PO4)2(s) + 4H+(aq) -> 3Ca^2+(aq) + 2H2PO4^-(aq).
Conclude that all three compounds are more soluble in acidic solutions due to the reaction of their anions with H+ ions, which shifts the equilibrium towards dissolution.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Solubility and pH
The solubility of certain compounds can be affected by the pH of the solution. In acidic conditions, compounds that can react with hydrogen ions (H+) may dissolve more readily. For example, carbonates like CaCO3 can react with acids to form soluble bicarbonate ions, increasing their solubility in acidic solutions compared to pure water.
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Net Ionic Equations
A net ionic equation represents the chemical species that are involved in a reaction, excluding spectator ions that do not change during the reaction. This format highlights the actual chemical change occurring, making it essential for understanding the dissolution process of compounds in different environments, such as acidic solutions.
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Dissolution Reactions
Dissolution reactions describe the process by which a solid solute dissolves in a solvent, forming ions in solution. For compounds like Ni(OH)2 and Ca3(PO4)2, the dissolution can be influenced by the presence of acids, which can react with the solute to produce soluble ions, thus altering their solubility in comparison to pure water.
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