Ch.10 Acids and Bases
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Problem 8
Write a balanced equation for the proton transfer reaction between hydrofluoric acid (HF) and ammonia (NH₃). Identify each conjugate acid-base pair, and rewrite the equilibrium arrows to indicate if the forward or reverse reaction is favored.Problem 9
From this electrostatic potential map of the amino acid alanine, identify the most acidic hydrogens in the molecule:
Problem 23
Show how ethylamine (C₂H₅NH₂) reacts with hydrochloric acid to form an ethylammonium salt.
Problem 28
One of these pictures represents a solution of HCl and one represents a solution of H 2 SO 4 . Which is which? a.
b.
Problem 34
Electrostatic potential maps of acetic acid (CH₃CO₂H) and ethyl alcohol (CH₃CH₂OH) are shown. Identify the most acidic hydrogen in each, and tell which of the two is likely to be the stronger acid.
Problem 38
What happens when a strong acid such as HBr is dissolved in water?Problem 39
What happens when a weak acid such as CH₃CO₂H is dissolved in water?Problem 40
What happens when a strong base such as KOH is dissolved in water?Problem 41
What happens when a weak base such as NH₃ is dissolved in water?Problem 42
What is the difference between a monoprotic acid and a diprotic acid? Give an example of each.Problem 43
What is the difference between H⁺ and H₃O⁺?Problem 51
How is K_w defined, and what is its numerical value at 25 °C?Problem 71
Rearrange the equation you wrote in Problem 10.50 to solve for [H₃O⁺] in terms of Kₐ.Problem 74
What is the difference between an acid and a base?Problem 76
Write equations to show how the substances listed in Problem 3.75 give ions when dissolved in water.Problem 76
The pH of a buffer solution containing 0.10 M acetic acid and 0.10 M sodium acetate is 4.74. Write the Henderson–Hasselbalch equation for this buffer.Problem 83
How does normality compare to molarity for monoprotic and polyprotic acids?Problem 84
Identify the number of equivalents per mole for each of the following acids and bases. H₃PO₄Problem 88
How many equivalents of an acid or base are in the following? 0.25 mol Mg(OH)₂Problem 90
What are the molarity and the normality of a solution made by dissolving 5.0 g of Ca(OH)₂ in enough water to make 500.0 mL of solution?Problem 91
What are the molarity and the normality of a solution made by dissolving 25 g of citric acid (triprotic,C₆H₅O₇H₃) in enough water to make 800 mL of solution?Problem 99
The dissociation of water into H₃O⁺ and OH⁻ ions depends on temperature. At 0 °C the [H₃O⁺] = 3.38 x 10⁻⁸ M, at 25 °C the [H₃O⁺] = 1.00 x 10⁻⁷ M, and at 50 °C the [H₃O⁺] = 2.34 x 10⁻⁷ M. What is the value of K_w at 0 °C and 50 °C.Problem 99
The dissociation of water into H₃O⁺ and OH⁻ ions depends on temperature. At 0 °C the [H₃O⁺] = 3.38 x 10⁻⁸ M, at 25 °C the [H₃O⁺] = 1.00 x 10⁻⁷ M, and at 50 °C the [H₃O⁺] = 2.34 x 10⁻⁷ M. Is the dissociation of water endothermic or exothermic?Problem 103
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. Write the Henderson–Hasselbalch equation for this buffer system.Problem 109
Obtain a package of Alka-Seltzer, an antacid, from the local drug store: Why does Alka-Seltzer foam and bubble when dissolved in water? Which ingredient is the antacid?Problem 110
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?Problem 111
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. One over-the-counter product lists the active ingredient as 'diphenhydramine HCl.' What does this designation mean?
