Chapter 15, Problem 12P

Write the chemical equation and the expression for the equilibrium constant, and calculate Kb for the reaction of each of the following ions as a base. (a) sulfate ion (b) citrate 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.

What is the equilibrium constant, K, for the reaction between HCN (Ka = 6.2 x 10⁻¹⁰) and OH⁻ at 25 °C?

Iron in drinking water is removed by precipitation of the Fe3+ ion by reaction with NaOH to produce iron(III) hydroxide. Write the balanced chemical equation and the net ionic equation for this reaction.

A laboratory technician wants to determine the aspirin content of a headache pill by acid-base titration. Aspirin has a Ka of 3.0 x 10−4. If the pill is dissolved in water to give a solution about 0.015 M, what is the pH of this solution? (Neglect dilution effects.)   If the solution in the problem above is then titrated against KOH solution, what will be the pH at the stoichiometric point.

The following 4 questions involve the titration of a 50.00 mL sample of 0.200 M chlorous acid, HClO2, with 0.200 M NaOH (aq., 25 oC). The Ka HClO2 = 1.11 x 10–2 1. Calculate the pH of the solution before any NaOH has been added.

Tin(II) oxide is amphoteric. Write balanced chemical equations for its reactions with an aqueous solution of hydrochloric acid and with an aqueous solution of sodium hydroxide. (Note: The hydroxide complex ion of tin(II) is[Sn(OH)3]-.)

The active ingredient of bleach such as Clorox is sodium hypochlorite (NaClO). Its conjugate acid, hypochlorous acid (HClO), has a Ka of 3.0 × 10–8. (a)The undiluted bleach contains roughly 1 M NaClO. Calculate the pH of 1 M NaClO solution.  (b)Some applications require extremely diluted bleach solution, such as swimming pools. Suppose the solution in (a) is diluted by 10,000 -fold. Calculate the pH of the diluted solution, and demonstrate that you can still neglect the autoionization of water in your calculation.  (c)Suppose the solution in (a) is diluted by 1million-fold, briefly explain how your approach will be different. Write the equation with [H3O+] as the unknown, but you do not need to solve it.

During the fermentation of wine, a buffer system consisting of tartaric acid and potassium hydrogen tartrate is produced by a biochemical reaction. Assuming that at some time the concentration of potassium hydrogen tartrate is twice that of tartaric acid, calculate the pH of the wine. The pKa of tartaric acid is 2.96.