Calculate the hydronium ion, H, O*, and hydroxide ion, OH¯, concentrations for a 0.0459 M NaOH solution. [OH¯]= [H,O*]=

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

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.

Calculate [OH-] and pH in a solution in which the hydrogen sulfite ion, HSO3-, is 0.429 M and the sulfite ion is (a) 0.0249 M (b) 0.247 M (c) 0.504 M (d) 0.811 M (e) 1.223 M

Consider 0.10 M solutions of the following compound: AlCl3, NaCN, KOH, CsClO4, and NaF. Place these solutions in order of increasing pH.

Use the same symbols as in Question 61 ( = anion, =OH) for the box below. (a) Fill in a similar box (representing one liter of the same solution) after 2 mol of H+ (2) have been added. Indicate whether the resulting solution is an acid, base, or buffer. (b) Follow the directions of part (a) for the resulting solution after 2 mol of OH- (2 ) have been added. (c) Follow the directions of part (a) for the resulting solution after 5 mol of OH- (5 ) have been added. (Hint: Write the equation for the reaction before you draw the results.)

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).

Aqueous Solutions of Acids, Bases, and Salts a For each of the following salts, write the reaction that occurs when it dissociates in water: NaCl(s), NaCN(s), KClO2(s), NH4NO3(s), KBr(aq), and NaF(s). b Consider each of the reactions that you wrote above, and identify the aqueous ions that could be proton donors (acids) or proton acceptors (bases). Briefly explain how you decided which ions to choose. c For each of the acids and bases that you identified in pan b, write the chemical reaction it can undergo in aqueous solution (its reaction with water). d Are there any reactions that you have written above that you anticipate will occur to such an extent that the pH of the solution will be affected? As pan of your answer, be sure to explain how you decided. e Assume that in each case above, 0.01 mol of the salt was dissolved in enough water at 25C to make 1.0 L of solution. In each case what additional information would you need in order to calculate the pH? If there are cases where no additional information is required, be sure to state that as well. f Say you take 0.01 mol of NH4CN and dissolve it in enough water at 25C to make 1.0 L of solution. Using chemical reactions and words, explain how you would go about determining what effect this salt will have on the pH of the solution. Be sure to list any additional information you would need to arrive at an answer.

Using the diagrams shown in Problem 10-117, which of the solutions would have the greatest buffer capacity, that is, greatest protection against pH change, when the following occurs? a. A strong acid is added to the solution. b. A strong base is added to the solution.

Calculate the pH of each of the following solutions. (a) 10.0 mL of 0.300 M hydrofluoric acid plus 30.0 mL of 0.100 M sodium hydroxide (b) 100.0 mL of 0.250 M ammonia plus 50.0 mL of 0.100 M hydrochloric acid (c) 25.0 mL of 0.200 M sulfuric acid plus 50.0 mL of 0.400 M sodium hydroxide