Textbook Question
An unknown salt is either KBr, NH4Cl, KCN, or K2CO3. If a 0.100 M solution of the salt is neutral, what is the identity of the salt?
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Ch.16 - Acid-Base Equilibria
Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970
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Table of contents
- Ch.1 - Introduction: Matter, Energy, and Measurement146
- Ch.2 - Atoms, Molecules, and Ions200
- Ch.3 - Chemical Reactions and Reaction Stoichiometry176
- Ch.4 - Reactions in Aqueous Solution155
- Ch.5 - Thermochemistry126
- Ch.6 - Electronic Structure of Atoms131
- Ch.7 - Periodic Properties of the Elements126
- Ch.8 - Basic Concepts of Chemical Bonding123
- Ch.9 - Molecular Geometry and Bonding Theories143
- Ch.10 - Gases147
- Ch.11 - Liquids and Intermolecular Forces91
- Ch.12 - Solids and Modern Materials122
- Ch.13 - Properties of Solutions126
- Ch.14 - Chemical Kinetics174
- Ch.15 - Chemical Equilibrium101
- Ch.16 - Acid-Base Equilibria139
- Ch.17 - Additional Aspects of Aqueous Equilibria146
- Ch.18 - Chemistry of the Environment72
- Ch.19 - Chemical Thermodynamics129
- Ch.20 - Electrochemistry142
- Ch.21 - Nuclear Chemistry101
- Ch.22 - Chemistry of the Nonmetals68
- Ch.23 - Transition Metals and Coordination Chemistry66
- Ch.24 - The Chemistry of Life: Organic and Biological Chemistry10
Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970Not the one you use?Change textbook
Chapter 16, Problem 90
Which member of each pair produces the more acidic aqueous solution: (a) ZnBr2 or CdCl2 (b) CuCl or Cu(NO3)2 (c) Ca(NO3)2 or NiBr2
Verified step by step guidance1
Identify the cation and anion in each compound: CuCl contains Cu^+ and Cl^-, while Cu(NO_3)_2 contains Cu^2+ and NO_3^-.
Consider the hydrolysis of the cations: Cu^+ is less likely to hydrolyze compared to Cu^2+, which can hydrolyze to form H^+ ions, increasing acidity.
Evaluate the anions: Cl^- is a weak conjugate base of a strong acid (HCl) and does not affect acidity, while NO_3^- is also a weak conjugate base of a strong acid (HNO_3) and does not affect acidity.
Compare the hydrolysis of the cations: Since Cu^2+ can hydrolyze to produce H^+ ions, Cu(NO_3)_2 is expected to produce a more acidic solution than CuCl.
Conclude that Cu(NO_3)_2 produces a more acidic aqueous solution than CuCl due to the hydrolysis of Cu^2+.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Acidity and pH
Acidity refers to the concentration of hydrogen ions (H+) in a solution, which determines its pH level. A lower pH indicates a more acidic solution. Understanding how different substances dissociate in water to release H+ ions is crucial for comparing their acidity.
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pH of Strong Acids and Bases
Metal Cation Behavior
Metal cations can influence the acidity of a solution based on their charge and size. Cations like Cu²⁺ can hydrolyze in water, forming acidic solutions by releasing H+ ions. The extent of this hydrolysis is key to determining which compound is more acidic.
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Complex Ion Formation
Complex ions form when metal cations coordinate with ligands, affecting their properties, including acidity. For example, Cu(NO3)2 may form complex ions that can alter the pH of the solution compared to simpler salts like CuCl. Understanding these interactions is essential for predicting acidity.
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Related Practice
Textbook Question
Predict whether aqueous solutions of the following substances are acidic, basic, or neutral: (d) 3CH3NH34NO3
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Textbook Question
Predict whether aqueous solutions of the following substances are acidic, basic, or neutral: (e) Na2SO3.
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Textbook Question
An unknown salt is either NaF, NaCl, or NaOCl. When 0.050 mol of the salt is dissolved in water to form 0.500 L of solution, the pH of the solution is 8.08. What is the identity of the salt?
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