The concentration of the hydronium ion in an aqueous solution at 25 °C is 0.0064 M. What is the concentration of the hydroxide ion?

Acids You make a solution by dissolving 0.0010 mol of HCl in enough water to make 1.0 L of solution. a Write the chemical equation for the reaction of HCl(aq) and water. b Without performing calculations, give a rough estimate of the pH of the HCl solution. Justify your answer. c Calculate the H3O+ concentration and the pH of the solution. d Is there any concentration of the base OH present in this solution of HCl(aq)? If so, where did it come from? e If you increase the OH concentration of the solution by adding NaOH, does the H3O+ concentration change? If you think it does, explain why this change occurs and whether the H3O+ concentration increases or decreases. f If you were to measure the pH of 10 drops of the original HCl solution, would you expect it to be different from the pH of the entire sample? Explain. g Explain how two different volumes of your original HCl solution can have the same pH yet contain different moles of H3O+. h If 1.0 L of pure water were added to the HCl solution, would this have any impact on the pH? Explain.

Students are often surprised to learn that organic acids, such as acetic acid, contain OH groups. Actually, all oxyacids contain hydroxyl groups. Sulfuric acid, usually written as H2SO4, has the structural formula SO2(OH)2, where S is the central atom. Identify the acids whose structural formulas are shown below. Why do they behave as acids, while NaOH and KOH are bases? a. SO(OH)2 b. ClO2(OH) c. HPO(OH)2

Boric acid, B(OH)3, is used as a mild antiseptic. What is the pH of a 0.015 M aqueous solution of boric acid? What is the degree of ionization of boric acid in this solution? The hydronium ion arises principally from the reaction B(OH)3(aq)+2H2O(l)B(OH)4(aq)+H3O+(aq)

Which of the diagrams in Problem 10-135 represents the substance that is the weakest electrolyte?

Ionization of the first proton from H2SO4 is complete (H2SO4 is a strong acid); the acid-ionization constant for the second proton is 1.1 102. a What would be the approximate hydronium-ion concentration in 0.100 M H2SO4 if ionization of the second proton were ignored? b The ionization of the second proton must be considered for a more exact answer, however. Calculate the hydronium-ion concentration in 0.100 M H2SO4, accounting for the ionization of both protons.

What is the pH of a solution obtained by mixing 235 mL of NaOH with a pH of 11.57 and 316 mL of Sr(OH)2 with a pH of 12.09? Assume that volumes are additive.

The weak base, CIO (hypochlorite ion), is used in the form of NaCIO as a disinfectant in swimming pools and water treatment plants. What are the concentrations of HCIO and OH and the pH of a 0.015 M solution of NaCIO?

Aluminum chloride, AlCl3, reacts with trimethyl-amine, N(CH3)3. What would you guess to be the product of this reaction? Explain why you think so. Describe the reaction in terms of one of the acid base concepts. Write an appropriate equation to go with this description. Which substance is the acid according to this acidbase concept? Explain.

The active ingredient formed by aspirin in the body is salicylic acid, C6H4OH(CO2H). The carboxyl group. (-CO2H) acts as a weak acid. The phenol group (an OH group bonded to an aromatic ring) also acts as an acid but a much weaker acid. List, in order of descending concentration, all of the ionic and molecular species present in a 0.001-M aqueous solution of C6H4OH(CO2H).