Concept explainers
Consider citric acid, H3C6H5O7, added to many soft drinks. The equilibrium constants for its step-wise ionization are
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Chapter 13 Solutions
Chemistry: Principles and Reactions
- 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 ionarrow_forwardMost naturally occurring acids are weak acids. Lactic acid is one example. CH3CH(OH)CO2H(s)+H2O(l)H3O+(aq)+CH3CH(OH)CO2(aq) If you place some lactic acid in water, it will ionize to a small extent, and an equilibrium will be established. Suggest some experiments to prow that this is a weak acid and that the establishment of equilibrium is a reversible process.arrow_forwardComplete each of these reactions by filling in the blanks. Predict whether each reaction is product-favored or reactant-favored, and explain your reasoning. (a) _________ (aq) + Br(aq) NH3(aq) + HBr(aq) (b) CH3COOH(aq) + CN(aq) ________ (aq) + HCN(aq) (c) ________ (aq)+H2O () NH3(aq) + OH(aq)arrow_forward
- 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.)arrow_forwardAcrylic acid is used in the polymer industry in the production of acrylates. Its K, is 5.6 X 10“’. What is the pH of a 0.11 M solution of acrylic acid, CH2CHCOOH?arrow_forwardWrite a balanced molecular equation for the preparation of each of the following salts, using an acidbase neutralization reaction. a. LiNO3 (lithium nitrate) b. BaCl2 (barium chloride) c. K3PO4 (potassium phosphate) d. Na2SO4 (sodium sulfate)arrow_forward
- Write chemical equations showing the individual proton-transfer steps that occur in aqueous solution for each of the following acids. a. H2C2O4 (oxalic acid) b. H2C4H4O6 (tartaric acid)arrow_forwardAcetic acid is a weak acid, meaning it does not fully dissociate in water. Instead, there is an equilibrium between the dissolved but undissociated molecule and the component ions: HOAc (aq) + H2O (l) ⇌ H3O+ (aq) + OAc– (aq)OAc– is an abbreviation for the acetate ion, CH3COO–, and H3O+ is the hydronium ion (lone protons, H+ (aq), do not exist!). (a) Write the equilibrium constant expression for the dissociation of acetic acid. (b) Vinegar sold commercially is typically 0.8 − 1.0 M acetic acid. A 1.00 M solution of acetic acid is measured by its pH to have an equilibrium concentration of 4.19×10−3 M for both acetate ions and hydronium ions at room temperature. Assuming [HOAc]0 = 1.00M, what is the equilibrium concentration of undissociated acetic acid [HOAc]eq to the correct number of significant figures? (c) What is the value of the equilibrium constant Keq for the dissociation according to the concentrations from part (b)? (d) When starting with completely un-dissociated…arrow_forwardGiven 0.01 M solutions of each of the following acids, which solution would have the lowest pH? -117 Hypoiodous acid (HOI), K = 2.3 x 10 Hypobromous acid (HOBr), K = 2.5 x 10 Lactic acid (HC₂H₂O₂), K = 1.3 x 10 Chlorous acid (HClO₂), K = 1.1 x 10²arrow_forward
- Indicate how the concentration of each aqueous species in the chemical equation changes to reestablish equilibrium after changing the concentration of a reactant or product. Also indicate how the pH changes. An up arrow indicates an increase in concentration, a down arrow indicates a decrease in concentration, and leaving it blank means there is no change in the concentration. HC\(aq)+H,O()=CN (aq)+H,0*(aq) pH after the concentration of HCN is increased after the concentration of CN is decreased Answer Bank careers privacy poliy thelp 口 )arrow_forwardThe ionization constant (Kb) of aniline (C6H5NH2) is 2.35 x 10–5. If 7.285 grams of aniline is dissolved in 100.0 mL of water, what are the equilibrium concentration of all species present?arrow_forwardPropionic acid, HC3H5O2, has Ka= 1.34 x 10–5. (a) What is the molar concentration of H3O+ in 0.15 M HC3H5O2 and the pH of the solution? (b) What is the Kb value for the propionate ion, C3H5O2–? (c) Calculate the pH of 0.15 M solution of sodium propionate, NaC3H5O2. (d) Calculate the pH of solution that contains 0.12 M HC3H5O2 and 0.25 M NaC3H5O2.arrow_forward
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