Textbook Question
Obtain a package of Alka-Seltzer, an antacid, from the local drug store:
b. Why does Alka-Seltzer foam and bubble when dissolved in water? Which ingredient is the antacid?
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Ch.10 Acids and Bases
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187
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Table of contents
- Ch.1 Matter and Measurements27
- Ch.2 Atoms and the Periodic Table20
- Ch.3 Ionic Compounds8
- Ch.4 Molecular Compounds23
- Ch.5 Classification & Balancing of Chemical Reactions12
- Ch.6 Chemical Reactions: Mole and Mass Relationships28
- Ch.7 Chemical Reactions: Energy, Rate and Equilibrium64
- Ch.8 Gases, Liquids and Solids24
- Ch.9 Solutions52
- Ch.10 Acids and Bases25
- Ch.11 Nuclear Chemistry22
- Ch.12 Introduction to Organic Chemistry: Alkanes57
- Ch.13 Alkenes, Alkynes, and Aromatic Compounds47
- Ch.14 Some Compounds with Oxygen, Sulfur, or a Halogen50
- Ch.15 Aldehydes and Ketones45
- Ch.16 Amines42
- Ch.17 Carboxylic Acids and Their Derivatives57
- Ch.18 Amino Acids and Proteins82
- Ch.19 Enzymes and Vitamins63
- Ch.20 Carbohydrates44
- Ch.21 The Generation of Biochemical Energy65
- Ch.22 Carbohydrate Metabolism45
- Ch.23 Lipids42
- Ch.24 Lipid Metabolism33
- Ch.25 Protein and Amino Acid Metabolism24
- Ch.26 Nucleic Acids and Protein Synthesis45
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187Not the one you use?Change textbook
Chapter 10, Problem 111a
Many allergy medications contain antihistamines, compounds that contain amine groups (R-NH2, where R refers to an organic functional group). Would you expect these compounds to be acidic, basic or neutral? Explain.
a. One over-the-counter product lists the active ingredient as "diphenhydramine HCl." What does this designation mean?
Verified step by step guidance1
Step 1: Begin by analyzing the chemical structure of amine groups (R-NH₂). Amines are nitrogen-containing compounds where the nitrogen atom has a lone pair of electrons. This lone pair allows amines to act as proton acceptors, making them basic in nature.
Step 2: Consider the designation 'diphenhydramine HCl.' The 'HCl' indicates that the compound is in its hydrochloride salt form. This is common for amine-containing drugs, as the amine group reacts with hydrochloric acid (HCl) to form a salt, which improves the compound's solubility in water.
Step 3: Understand the reaction between the amine group and HCl. The amine group (R-NH₂) acts as a base and accepts a proton (H⁺) from HCl, forming the ammonium ion (R-NH₃⁺). This process neutralizes the basicity of the amine group, resulting in a salt form.
Step 4: Evaluate the acidity, basicity, or neutrality of the compound. In its hydrochloride salt form, diphenhydramine HCl is neutral because the basic amine group has been protonated and paired with the chloride ion (Cl⁻), balancing the charge.
Step 5: Conclude that while amines are typically basic, the presence of 'HCl' in diphenhydramine HCl indicates that the compound has been converted into a neutral salt form for pharmaceutical use.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Antihistamines and Amine Groups
Antihistamines are compounds that block the action of histamine, a substance in the body that causes allergic symptoms. Many antihistamines contain amine groups (R-NH₂), which are basic due to the presence of a nitrogen atom that can accept protons. This basicity influences their interaction with biological systems and their overall pharmacological effects.
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0:54
Amine Classification Example 1
Acidity and Basicity of Compounds
The acidity or basicity of a compound is determined by its ability to donate or accept protons (H⁺ ions). Compounds with amine groups are generally considered basic because they can accept protons, leading to a positive charge. Understanding this property is crucial for predicting the behavior of antihistamines in the body and their effectiveness in treating allergies.
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01:04Balancing Redox Reactions: Basic Solutions
Diphenhydramine HCl Designation
The designation 'diphenhydramine HCl' indicates that diphenhydramine is combined with hydrochloric acid to form a salt. This salt form enhances the solubility and stability of the drug, making it easier to administer and absorb in the body. The 'HCl' signifies that the diphenhydramine is in its hydrochloride form, which is common for many pharmaceutical compounds.
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02:41Buffer Solution Example
Related Practice
Textbook Question
One of the buffer systems used to control the pH of blood involves the equilibrium between H2PO4– and H2PO42–. The pKa for H2PO42– is 7.21.
a. Write the Henderson-Hasselbalch equation for this buffer system.
Textbook Question
Research the composition of 'smelling salts'—a product that is used to rouse people who have lost consciousness.What are the chemical reactions that generate the 'active' component?