Textbook Question
An aqueous solution contains 1.2 mM of total ions. (a) If the solution is NaCl(aq), what is the concentration of chloride ion?
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Ch.4 - Reactions in Aqueous Solution
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232
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Table of contents
- Ch.1 - Introduction: Matter, Energy, and Measurement177
- Ch.2 - Atoms, Molecules, and Ions231
- Ch.3 - Chemical Reactions and Reaction Stoichiometry216
- Ch.4 - Reactions in Aqueous Solution189
- Ch.5 - Thermochemistry175
- Ch.6 - Electronic Structure of Atoms168
- Ch.7 - Periodic Properties of the Elements150
- Ch.8 - Basic Concepts of Chemical Bonding177
- Ch.9 - Molecular Geometry and Bonding Theories200
- Ch.10 - Gases179
- Ch.11 - Liquids and Intermolecular Forces113
- Ch.12 - Solids and Modern Materials154
- Ch.13 - Properties of Solutions157
- Ch.14 - Chemical Kinetics199
- Ch.15 - Chemical Equilibrium128
- Ch.16 - Acid-Base Equilibria164
- Ch.17 - Additional Aspects of Aqueous Equilibria163
- Ch.18 - Chemistry of the Environment105
- Ch.19 - Chemical Thermodynamics164
- Ch.20 - Electrochemistry171
- Ch.21 - Nuclear Chemistry122
- Ch.22 - Chemistry of the Nonmetals82
- Ch.23 - Transition Metals and Coordination Chemistry79
- Ch.24 - The Chemistry of Life: Organic and Biological Chemistry16
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232Not the one you use?Change textbook
Chapter 4, Problem 7
In each of the following pairs, indicate which has the higher concentration of Cl- ion: (a) 0.10 M AlCl3 solution or a 0.25 M LiCl solution (b) 150 mL of a 0.05 M MnCl3 solution or 200 mL of 0.10 M KCl solution (c) a 2.8 M HCl solution or a solution made by dissolving 23.5 g of KCl in water to make 100 mL of solution.
Verified step by step guidance1
Step 1: For each solution, determine the number of moles of Cl⁻ ions produced per mole of compound. For example, AlCl₃ dissociates into one Al³⁺ ion and three Cl⁻ ions, so it produces 3 moles of Cl⁻ per mole of AlCl₃.
Step 2: Calculate the concentration of Cl⁻ ions for each solution by multiplying the molarity of the solution by the number of Cl⁻ ions produced per formula unit. For example, for a 0.10 M AlCl₃ solution, the concentration of Cl⁻ ions is 0.10 M × 3 = 0.30 M.
Step 3: For part (b), calculate the total moles of Cl⁻ ions in each solution by multiplying the volume (in liters) by the molarity and the number of Cl⁻ ions per formula unit. For example, for 150 mL of 0.05 M MnCl₃, convert the volume to liters and calculate the moles of Cl⁻.
Step 4: Compare the concentrations or total moles of Cl⁻ ions calculated in the previous steps for each pair of solutions to determine which has the higher concentration of Cl⁻ ions.
Step 5: For part (c), convert the mass of KCl to moles using its molar mass, then calculate the concentration of Cl⁻ ions in the solution by dividing the moles of Cl⁻ by the volume of the solution in liters. Compare this with the concentration of Cl⁻ ions in the 2.8 M HCl solution.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Ionic Dissociation
Ionic dissociation refers to the process by which an ionic compound separates into its constituent ions when dissolved in a solvent, typically water. For example, when AlCl3 dissolves, it dissociates into one Al³⁺ ion and three Cl⁻ ions, resulting in a higher concentration of Cl⁻ ions compared to a compound that dissociates into fewer ions.
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Ionic Salts
Molarity and Concentration
Molarity (M) is a measure of concentration defined as the number of moles of solute per liter of solution. It is crucial for comparing solutions, as higher molarity indicates a greater amount of solute in a given volume. Understanding how to calculate and compare molarity helps determine which solution has a higher concentration of specific ions.
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Volume and Dilution Effects
The volume of a solution affects the total number of moles of solute present. When comparing solutions, it is important to consider both the concentration and the volume to find the total amount of a specific ion. For instance, a larger volume of a lower concentration solution may contain more total moles of an ion than a smaller volume of a higher concentration solution.
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Related Practice
Textbook Question
You are presented with a white solid and told that due to careless labeling it is not clear if the substance is barium chloride, lead chloride, or zinc chloride. When you transfer the solid to a beaker and add water, the solid dissolves to give a clear solution. Next an Na2SO41aq2 solution is added and a white precipitate forms. What is the identity of the unknown white solid?
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Textbook Question
Which of the following ions will always be a spectator ion in a precipitation reaction? (a) Cl- (b) NO3- (c) NH4+ (d) S2- (e) SO42-
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Textbook Question
What kind of reaction is the 'water-splitting' reaction?H2O(l)¡H2(g) + ½ O2(g)(a) an acid-base reaction(b) a metathesis reaction(c) a redox reaction(d) a precipitation reaction
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