6. For each of the following neutralization reactions, predict the products & balance the equation: a. HCI + KOH ₹ KCl + H₂O b. 2 HCN + Ca(OH)₂ Ca(CN)₂ + 2 H₂O 7. Identify the acid and the base (for the forward direction) in each of the following reactions: a. BH3 + H₂O → BH4+ + OH- Base Acid b. CH3COOH + H₂O → CH3COO- + H3O+ Acid Base c. HCO3 + H₂O → CO3²- + H3O+ Acid Base d. HCN + H₂O → CN¯ + H3O+ Acid Base e. HNO3 + H₂O → NO3 + H3O+ Acid Base

If one mole of the following compounds were each placed into separate beakers containing the same amount of water, rank the Cl(aq) concentrations from highest to lowest (some may be equivalent): KCl, AlCl3, PbCl2, NaCl, HCl, NH3, KOH, and HCN.

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.

You have a solution of the weak acid HA and add some HCl to it. What are the major species in the solution? What do you need to know to calculate the pH of the solution, and how would you use this information? How does the pH of the solution of just the HA compare with that of the final mixture? Explain.

Calculate [CO32] in a 0.010-M solution of CO2 in water (usually written as H2CO3). If all the CO32 in this solution comes from the reaction HCO3(aq)H+(aq)+CO32(aq) what percentage of the H+ ions in the solution is a result of the dissociation of HCO3? When acid is added to a solution of sodium hydrogen carbonate (NaHCO3), vigorous bubbling occurs. How is this reaction related to the existence of carbonic acid (H2CO3) molecules in aqueous solution?

Consider a 0.33 M solution of the diprotic acid H2X. H2X H+(aq)+ HX(aq)Ka1=3.3 10 4 HX H+(aq)+ X2(aq)Ka2=9.7 10 8 Calculate the pH of the solution and estimate [HX-] and [X2-].

The pH of 1.0 108 M hydrochloric acid is not 8.00. The correct pH can be calculated by considering the relationship between the molarities of the three principal ions in the solution (H+, Cl, and OH). These molarities can be calculated from algebraic equations that can be derived from the considerations given below. a. The solution is electrically neutral. b. The hydrochloric acid can be assumed to be 100% ionized. c. The product of the molarities of the hydronium ions and the hydroxide ions must equal Kw. Calculate the pH of a 1.0 108-M HCl solution.

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

Write two BrnstedLowry acid-base reactions and show how they represent proton-transfer reactions.

For conjugate acidbase pairs, how are Ka and Kb related? Consider the reaction of acetic acid in water CH3CO2H(aq)+H2O(l)CH3CO2(aq)+H3O+(aq) where Ka = 1.8 105 a. Which two bases are competing for the proton? b. Which is the stronger base? c. In light of your answer to part b. why do we classify the acetate ion (CH3CO2) as a weak base? Use an appropriate reaction to justify your answer. In general, as base strength increases, conjugate acid strength decreases. Explain why the conjugate acid of the weak base NH3 is a weak acid. To summarize, the conjugate base of a weak acid is a weak base and the conjugate acid of a weak base is a weak acid (weak gives you weak). Assuming Ka for a monoprotic strong acid is 1 106, calculate Kb for the conjugate base of this strong acid. Why do conjugate bases of strong acids have no basic properties in water? List the conjugate bases of the six common strong acids. To tie it all together, some instructors have students think of Li+, K+, Rb+, Cs+, Ca2+, Sr2+, and Ba2+ as the conjugate acids of the strong bases LiOH, KOH. RbOH, CsOH, Ca(OH)2, Sr(OH)2, and Ba(OH)2. Although not technically correct, the conjugate acid strength of these cations is similar to the conjugate base strength of the strong acids. That is, these cations have no acidic properties in water; similarly, the conjugate bases of strong acids have no basic properties (strong gives you worthless). Fill in the blanks with the correct response. The conjugate base of a weak acid is a_____base. The conjugate acid of a weak base is a_____acid. The conjugate base of a strong acid is a_____base. The conjugate acid of a strong base is a_____ acid. (Hint: Weak gives you weak and strong gives you worthless.)