3. Soda is a solution of CO2 in water. Is this acidic, basic, or neutral ? Now consider blood which has a pH~7.2, how does a build-up of CO2 affect the pH of the blood?

Hydrogen, H2S, and sodium acetate, NaCH3CO2 are mixed in water. Using Table 16.2, write a balanced equation for the acid-base reaction that could in principle, occur. Does the equilibrium lie toward the products or the reactants?

Consider an aqueous solution of HF. The molar heat of formation for aqueous HF is -320.1 kJ/mol. (a) What is the pH of a 0.100 M solution of HF at 100C? (b) Compare with the pH of a 0.100 M solution of HF at 25C.

Use Table 15.2 to decide whether the species on the left or those on the right are favored by the reaction. a NH4++H2PO4NH3+H3PO4 b HCN+HSCN+H2S c HCO3+OHCO32+H2O d Al(H2O)63++OHAl(H2O)5OH2++H2O

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.

A solution of sodium cyanide, NaCN, has a pH of 12.10. How many grams of NaCN are in 425 mL of a solution with the same pH?

Consider the following ions: NH4+, CO32, Br, S2, and ClO4. (a) Which of these ions in water gives an acidic solution and which gives a basic solution? (b) Which of these anions will have no effect on the pH of an aqueous solution? (c) Which ion is the strong base? (d) Write a chemical equation for the reaction of each basic anion with water.

Strong Acids, Weak Acids, and pH Two 0.10-mol samples of the hypothetical monoprotic acids HA(aq) and HB(aq) are used to prepare 1.0-L stock solutions of each acid. a Write the chemical reactions for these acids in water. What are the concentrations of the two acid solutions? b One of these acids is a strong acid, and one is weak. What could you measure that would tell you which acid was strong and which was weak? c Say that the HA(aq) solution has a pH of 3.7. Is this the stronger of the two acids? How did you arrive at your answer? d What is the concentration of A(aq) in the HA solution described in part c? e If HB(aq) is a strong acid, what is the hydronium-ion concentration? f In the solution of HB(aq), which of the following would you expect to be in the greatest concentration: H3O+(aq), B(aq), HB(aq), or OH(aq)? How did you decide? g In the solution of HA(aq), which of the following would you expect to be in the greatest concentration: H3O+(aq), A+(aq), HA(aq), or OH(aq)? How did you decide? h Say you add 1.0 L of pure water to a solution of HB. Would this water addition make the solution more acidic, make it less acidic, or not change the acidity of the original solution? Be sure to fully justify your answer. i You prepare a 1.0-L solution of HA. You then take a 200-mL sample of this solution and place it into a separate container. Would this 200 mL sample be more acidic, be less acidic, or have the same acidity as the original 1.0-L solution of HA(aq)? Be sure to support your answer.

(a) What is the pH of a 0.105 M HCl solution? (b) What is the hydronium ion concentration in a solution with a pH of 2.56? Is the solution acidic or basic? (c) A solution has a pH of 9.67. What is the hydronium ion concentration in the solution? Is the solution acidic or basic? (d) A 10.0-mL sample of 2.56 M HCl is diluted with water to 250. mL What is the pH of the dilute solution?

Equal molar quantities of sodium hydroxide and sodium hydrogen phosphate (Na2HPO4) are mixed. (a) Write the balanced, net ionic equation for the acid-base reaction that can, in principle, occur. (b) Does the equilibrium lie to the right or left?