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.

From this electrostatic potential map of the amino acid alanine, identify the most acidic hydrogens in the molecule:

<IMAGE>

Show how ethylamine (C₂H₅NH₂) reacts with hydrochloric acid to form an ethylammonium salt.

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.

<IMAGE>

What happens when a strong acid such as HBr is dissolved in water?

What happens when a weak acid such as CH₃CO₂H is dissolved in water?

What happens when a strong base such as KOH is dissolved in water?

What happens when a weak base such as NH₃ is dissolved in water?

What is the difference between a monoprotic acid and a diprotic acid? Give an example of each.

What is the difference between H⁺ and H₃O⁺?

How is K_w defined, and what is its numerical value at 25 °C?

Rearrange the equation you wrote in Problem 10.50 to solve for [H₃O⁺] in terms of K_a.

The pH of a buffer solution containing 0.10 M acetic acid and 0.10 M sodium acetate is 4.74.

a. Write the Henderson–Hasselbalch equation for this buffer.

How does normality compare to molarity for monoprotic and polyprotic acids?

Identify the number of equivalents per mole for each of the following acids and bases.

b. H₃PO₄

How many equivalents of an acid or base are in the following?

a. 0.25 mol Mg(OH)₂

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?

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?

A solution is prepared by bubbling 15.0 L of HCl(g) at 25 °C and 1 atm into 250.0 mL of water.

a. Assuming all the HCl dissolves in the water, how many moles of HCl are in solution?

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.

b. What is the value of K_w at 0 °C and 50 °C?

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.

c. Is the dissociation of water endothermic or exothermic?

One of the buffer systems used to control the pH of blood involves the equilibrium between H₂PO₄^– and H₂PO₄^2–. The pK_a for H₂PO₄^2– is 7.21.

a. Write the Henderson-Hasselbalch equation for this buffer system.

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?

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?