Textbook Question
Calculate the molar solubility of PbCrO4 in: (a) Pure Water(d) 1.0 x 10^-3 M K2CrO4
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Ch.17 - Applications of Aqueous Equilibria
McMurry8th EditionChemistryISBN: 9781292336145
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Table of contents
- Ch.1 - Chemical Tools: Experimentation & Measurement143
- Ch.2 - Atoms, Molecules & Ions134
- Ch.3 - Mass Relationships in Chemical Reactions149
- Ch.4 - Reactions in Aqueous Solution157
- Ch.5 - Periodicity & Electronic Structure of Atoms92
- Ch.6 - Ionic Compounds: Periodic Trends and Bonding Theory73
- Ch.7 - Covalent Bonding and Electron-Dot Structures47
- Ch.8 - Covalent Compounds: Bonding Theories and Molecular Structure51
- Ch.9 - Thermochemistry: Chemical Energy104
- Ch.10 - Gases: Their Properties & Behavior138
- Ch.11 - Liquids & Phase Changes43
- Ch.12 - Solids and Solid-State Materials56
- Ch.13 - Solutions & Their Properties98
- Ch.14 - Chemical Kinetics79
- Ch.15 - Chemical Equilibrium107
- Ch.16 - Aqueous Equilibria: Acids & Bases94
- Ch.17 - Applications of Aqueous Equilibria125
- Ch.18 - Thermodynamics: Entropy, Free Energy & Equilibrium66
- Ch.19 - Electrochemistry130
- Ch.20 - Nuclear Chemistry73
- Ch.21 - Transition Elements and Coordination Chemistry122
- Ch.22 - The Main Group Elements155
- Ch.23 - Organic and Biological Chemistry43
Chapter 17, Problem 114b
Which of the following compounds are more soluble in acidic solution than in pure water? Write a balanced net ionic equation for each dissolution reaction. (b) Fe(OH)3
Verified step by step guidance1
Identify the nature of the compound Fe(OH)3. It is a sparingly soluble iron(III) hydroxide, which tends to dissolve better in acidic solutions due to the reaction of its hydroxide ions with the hydrogen ions in the acid.
Write the dissolution reaction of Fe(OH)3 in water: Fe(OH)3(s) ⇌ Fe^{3+}(aq) + 3OH^{-}(aq). This reaction shows that Fe(OH)3 dissociates into iron(III) ions and hydroxide ions in water.
Consider the common ion effect and the solubility product (Ksp) of Fe(OH)3. In pure water, the solubility is limited and governed by its Ksp.
Add an acid (source of H^+ ions) to the system. The added H^+ ions will react with the OH^{-} ions to form water: H^+(aq) + OH^{-}(aq) → H2O(l). This reaction decreases the concentration of OH^{-} ions in the solution.
Write the net ionic equation for the dissolution of Fe(OH)3 in an acidic solution, showing how the reaction shifts to dissolve more Fe(OH)3: Fe(OH)3(s) + 3H^+(aq) → Fe^{3+}(aq) + 3H2O(l). This equation demonstrates that in the presence of excess H^+, the solubility of Fe(OH)3 increases as the hydroxide ions are neutralized.
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, some metal hydroxides, like Fe(OH)3, can dissolve more readily due to the formation of soluble metal complexes or the reaction of hydroxide ions with protons, leading to increased solubility.
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Net Ionic Equations
A net ionic equation represents the chemical species that are involved in a reaction, excluding spectator ions. It highlights the actual chemical change occurring in the solution, which is particularly useful for understanding the dissolution process of compounds in different pH environments.
Dissolution of Metal Hydroxides
Metal hydroxides, such as Fe(OH)3, typically have low solubility in water. However, in acidic solutions, they can dissolve by reacting with hydrogen ions to form soluble metal ions, such as Fe^3+, thus demonstrating a shift in solubility based on the solution's acidity.
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