Ch.15 - Acid and Base EquilibriumWorksheetSee all chapters
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Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Associated with any weak acid or weak base is a Ka or Kb value respectively. 

Acid and Base Dissociation Constants.

Concept #1: Understanding Ka and Kb Expressions.

Weak acids possess a Ka value less than 1, while weak bases possess a Kb value less than 1. The equilibrium expressions of Ka and Kb are the same as other equilibrium constants we’ve seen. 

Concept #2: Understanding Ka and Kb. 

The greater the Ka value then the stronger the acid, while the greater the Kb the stronger the base. Ka and Kb are connected by the following equation: 

Practice: If the Kb of NH3 is 1.76 x 10-5, determine the acid dissociation constant of its conjugate acid. 

Example #1: Knowing that HF has a higher Ka value than CH3COOH, determine, if possible, in which direction the following equilibrium lies.

 

HF (aq) + CH3COO (aq) ⇌ F (aq) + CH3COOH (aq)

 

a)  Equilibrium lies to the left.

b)  Equilibrium lies to the right.

c)  Equilibrium is equal and balanced.

d)  Not enough information given. 

Example #2: What is the equilibrium constant for the following reaction and determine if reactants or products are favored. 

 

       HCN (aq)  +  ClO2 (aq)  ⇌ CN (aq)  +  HClO2 (aq)

 

The acid dissociation constant of HCN is 4.9 x 10-10 and the acid dissociation of HClO2 is 1.1 x 10-2.

       HCN (aq)  +  H2O (aq)  ⇌ CN (aq)  +  H3O+ (aq)

       HClO2 (aq)  +  H2O (aq)  ⇌ ClO2 (aq)    +  H3O+ (aq)

Example #3: Which of the following solutions will have the lowest pH?

  1. 0.25 M HC2F3O2
  2. 0.25 M HIO4
  3. 0.25 M HC3H5O3
  4. 0.25 M H2CO3
  5. 0.25 M HSeO4

Practice: Which Bronsted-Lowry base has the greatest concentration of hydroxide ions? 

Practice: Which Bronsted-Lowry acid has the weakest conjugate base?

Additional Problems
Given the list of weak acids and their K a values, which is the  strongest weak acid? a. HCN; 4.9 x 10 -10 b. HClO; 2.9 x 10-8 c. HIO; 2.3 x 10-11 d. HCO2H; 1.8 x 10-4 e. CH3CO2H; 1.8 x 10-5  
Which of the following bases is the STRONGEST? The base is followed by its K b. A) (CH3CH2)2NH, 8.6 × 10-4 B) CH3NH2, 4.4 × 10-4 C) C6H5NH2, 4.0 × 10-10 D) NH3, 1.76 × 10-5 E) C5H5N, 1.7 × 10-9
Which of the following compounds has the strongest conjugate acid? a) C6H5NH2        (Kb = 3.9 x 10 -10) b) (CH3)3N        (Kb =  6.4 x 10 -5) c)  NH3               (Kb =  1.75 x 10 -5) d)  CO32-           (Kb =  1.8 x 10 -4)
Which of the following will have the weakest conjugate base? A. Hydrocyanic acid, HCN (Ka = 4.9 x 10-10)  B. Benzoic acid, HC7H5O2  (Ka = 6.5 x 10-5​)  C. Hypochlorous acid, HCIO (Ka = 2.9 x 10-8​)  D. Phenol, HC6H5O (Ka = 1.3 x 10-10​)  E. Cyanic acid, HCNO (Ka = 2.0 x 10-4​) 
Which of the following statements is/ are correct. i. The ethylammonium ion, C2H5NH3+, has a pKa = 10.75 ii. The hypobromite ion, BrO - has a pKb = 8.55 iii. The weaker the weak acid, the stronger its conjugate base. A. i only B. ii only C. iii only D. i and ii E. i and iii
The equilibrium constant for autoionization of water (Kw) is always 1.0 X 10 -14.  a. True b. False
The base-dissociation constant, K b, for pyridine (C 5H 5N) is 1.4 × 10 −9.  The acid-dissociation constant, K a, for the pyridinium ion (C 5H 5NH +) is __________. A) 1.4 × 10 −23      B) 1.0 × 10 −7      C) 7.1 × 10 −4     D) 7.1 × 10 −6      E) 1.4 × 10 −5
Calculate the value of Kb for the conjugate of the weak acid HNO 2. A. 4.6 x 10-4 B. 4.2 x 1010 C. 2.2 x 10-11 D. 4.6 x 10-18 E. 1.2 x 10-17
Which of the following bases is the  STRONGEST? The base is followed by its Kb. A) (CH3CH2)2NH, 8.6 x 10-4 B) CH3NH2, 4.4 x 10-4 C) C6H5NH2, 4.0 x 10-10 D) NH3, 1.76 x 10-5 E) C5H5N, 1.7 x 10-9
Determine the Kb for CN1- at 25°C. The Ka for HCN is 4.9 x 10-10. A) 4.9 x 10-14 B) 2.3 x 10-9 C) 1.4 x 10-5 D) 2.0 x 10-5 E) 3.7 x 10-7
Which of the following solutions has the highest pH? A) 0.40 M CH3COOH B) 0.40 M HClO4 C) 0.40 M HCOOH
Consider two aqueous solutions of equal concentration: chlorous acid (HClO2, Ka = 1.1 x10 -2 ) and phenol (HC6H5O, Ka = 1.3 x10 -10) Which statement is true? A) HClO2 produces more [H3O+] than HC6H5O B) HClO2 is basic compared with HC6H5O C) HClO2 produces less [H3O+ ] than HC6H5O D) HClO2 is a strong acid E) ClO2– produces more [OH−] than C6H5O–
Which of the following is the strongest base? A) CH3NH2 , Kb = 4.4 x 10-4 B) C5H5N, Kb = 1.7 x 10-9 C) H2NCONH2, Kb = 1.5 x 10-14 D) NH3, Kb = 1.8 x 10-5 E) C2H5NH2, Kb = 5.6 x 10-4
The ion-product constant for water, Kw, is 1.0 x 10 -14 at 25 oC and 3.8 x 10 -14 at 40 oC. Is the auto ionization of water endothermic or exothermic?
Which of the following organic substances has the strongest conjugate base? 1. hydrochloric acid 2. trimethylamine (pKa = 9.80) 3. glutamic acid (pKa = 2.13) 4. benzylamine (pKa = 9.33) 5. quinine (pKa1 = 8.52) 6. cyclohexylamine (pKa = 10.66) 7. pyridine (pKa = 5.25)
The following equation represents what property of water? H2O ⇌ H + + OH –   a. it is oxidizing b. it is reducing c. it auto-ionizes d. it is both oxidizing and reducing e. it disproportionates
Given the Ka values (in parentheses) for the following acids: HCl (Ka is very large) HNO2 (Ka = 4.0 x 10 –4 ); HF (Ka = 7.2 x 10 –4 ) CH3COOH (Ka = 1.8 x 10 –5 ) HCN (Ka = 6.2 x 10 –10) C6H5COOH (Ka = 6.3 x 10 –5 ) Rank (or list) these acids in order of decreasing strength (strongest first). A. HCl > HF > HNO2 > C6H5COOH > CH3COOH > HCN B. HCl > HF > HNO2 > CH3COOH > C6H5COOH > HCN C. HCN > CH3COOH > C6H5COOH > HNO2 > HF > HCl D. HCl > HNO2 > HF > CH3COOH > C6H5COOH > HCN E. HCN > C6H5COOH > CH3COOH > HF > HNO2 > HCl
Which of the following relationships is incorrect? Assume 25° C.  
Which of the following statements about the autoprotolysis of water is not true? A. The concentration of protons and hydroxides in pure water is always equal B. The pH of neutral water is about 7 at room temperature C. The process is endothermic D. The measured proton concentration is the same in hot and cold water
Rank the conjugate bases of the following weak acids from strongest to weakest. Acid                                    K    a butyric acid                       1.51 x 10   -5 hydrofluoric acid               6.76 x 10  -4 phenol                               1.02 x 10   -10 A. hydrofluoric acid, butyric acid, phenol B. butyric acid, hydrofluoric acid, phenol C. phenol, butyric acid, hydrofluoric acid D. hydrofluoric acid, phenol, butyric acid
Which substance is the strongest acid in the above table? a) HClO b) C6H5COOH c) HNO2 d) C6H5OH e) HCO3–
Which of the following is the strongest base? A) CH3NH2, Kb = 4.4 x 10-4 B) C5H5N, Kb = 1.7 x 10-9 C) H2NCONH2, Kb = 1.5 x 10-14 D) NH3, Kb = 1.8 x 10-5 E) C2H5NH2, Kb = 5.6 x 10-4
The average pH of normal arterial blood is 7.40. At normal body temperature (37oC), Kw=2.4 10-14.Calculate [H+] and [OH-] for blood at this temperature.
The average pH of normal arterial blood is 7.40. At normal body temperature (37oC), Kw=2.4 10-14.Calculate pOH for blood at this temperature.
What is the value of Kw at 25 oC?
Acidity of the hypohalous oxyacids (YOH) as a function of electronegativity of Y.At equilibrium, which of the two species with a halogen atom (green) is present in greater concentration?
Butyric acid is responsible for the foul smell of rancid butter. The pKa of butyric acid is 4.84.Calculate the pKb for the butyrate ion.
Use the acid-dissociation constants in the following table to arrange these oxyanions from strongest base to weakest. Name Formula Ka1 Ka2 Ka3 Ascorbic H2C6H6O6 8.0 10-5 1.6 10-12 ; Carbonic H2CO3 4.3 10-7 5.6 10-11 ; Citric H3C6H5O7 7.4 10-4 1.7 10-5 4.0 10-7 Oxalic H2C2O4 5.9 10-2 6.4 10-5 ; Phosphoric H3PO4 7.5 10-3 6.2 10-8 4.2 10-13 Sulfurous H2SO3 1.7 10-2 6.4 10-8 ; Sulfuric H2SO4 Large 1.2 10-2 ; Tartaric H2C4H4O6 1.0 10-3 4.6 10-5 ;
What is the relationship between the acid ionization constant for a weak acid (Ka) and the base ionization constant for its conjugate base (Kb )?
If you know the Ka of an acid, how do you determine the Kb of its conjugate base?
What is the value of K b for the formate anion, HCOO-? Ka (HCOOH) = 2.1 x 10-4 A) -2.1 x 10-4 B) 2.1 x 10-4 C) 6.9 x 10-6 D) 4.8 x 10-11
The Ka for HC2H3O2 is 1.8 x 10-5. What is the value of  Kb for C2H3O2-?
Of the following acids, __________ is the strongest acid.  A) HCHO2 B) HClO C) HF D) HOAc E) HOAc and HCHO2
Hydrofluoric acid, HF, is often used to etch glass. What is the value of K b for the fluoride ion, F-?A. 3.5 x 10-18B. 3.5 x 1010C. 1.0 x 10-14D. 7.1 x 10-19E. 2.9 x 10-11
Given the following acids and Ka values:  What is the order of increasing base strength?a. CN-, ClO4-, F-, OAC-b. ClO4-, OAC, CN-, F-c. CN-, F-, OAC-, ClO4-d. ClO4-, F-, OAC-, CN-e. CN-, OAC-, F-, ClO4
Which of the following is the correct equilibrium expression for the autoionization of water?
What is the Kb for C2H3O2- if the Ka for HC2H3O2 is 1.8 x 10-5?
What is the correct equation for the ion product of water at 25 °C?  
The pKa of acetic acid, CH3COOH, is 4.76. What is the value of the equilibrium constant Keq, for the following equilibrium? The concentration of water in a dilute aqueous solution is 55 M.CH3COOH + H2O ⇌ H3O+ + CH3COO-
a. Given that Ka for HClO is 4.0 × 10-8 at 25°C, what is the value of Kb for ClO– at 25°C? b. Given that Kb for CH3CH2NH2 is 6.3 × 10-4 at 25°C, what is the value of Ka for CH3CH2NH3+ at 25°C?
Ka for HC2H3O2: 1.8 x 10 -5Ka for HCO3-: 4.3 x 10 -7Using the Ka's for HC2H3O2 and HCO3, calculate the Kb's for the C2H3O2- and CO32- ions.
The Ka for HCN is 4.9 x 10-10. What is the value of  Kb for CN-?
If you know Kb for ammonia, NH3, you can calculate the equilibrium constant, Ka, for this reaction by the equation: NH4 +  ⇌  NH3  +  H + a) Ka = KwKb b) Ka = Kw / Kb c) Ka = 1 / Kb d) Ka = Kb / Kw
The pKa of formic acid is 3.75. What is the K a of formic acid?
Given: acetic acid, pKa = 4.75 HClO2, pKa = 2.00 HF, pKa = 3.45 The order of these acids from strongest to weakest is a) HClO2 > HF > acetic acid b) acetic acid > HF > HClO 2 c) HF > HClO 2 > acetic acid d) HClO2 > acetic acid > HF e) HF > acetic acid > HClO 2
Which of the following is the correct equilibrium expression for the autoionization of water?A) K = [H2O]2B) K = [OH][H3O]/[H2O]2C) Kw = [OH][H3O]D) Kw = [OH-][H3O+]E) Kw = [H3O+]/[OH-]
a. What is the K a reaction of HCN? The Ka of HCN is 6.2 × 10-10.b. What is Kb value for CN– at 25°C?
Complete the Kw expression for the autoionization of water.Kw = 1.00 x 10-14
Which of the following is the STRONGEST? The base is followed by its pKb.A) (CH3CH2)2NH,      3.07B) CH3NH2,               3.36C) C6H5NH2,             9.40D) NH3,                      4.75E) C5H5N,                  8.77
Like any equilibrium constant, Kw changes with temperature.(a) Given that autoionization is endothermic, how does Kw change with rising T? Explain with a reaction that includes heat as reactant or product.
Like any equilibrium constant, K w changes with temperature.(b) In many medical applications, the value of K w at 37°C (body temperature) may be more appropriate than the value at 25°C, 1.0×10−14. The pH of pure water at 37°C is 6.80. Calculate K w, pOH, and [OH−] at this temperature.
Write a chemical equation that illustrates the autoionization of water.
Write the expression for the ion-product constant for water, Kw.
Write an equation for the autoionization of water and an expression for the ion product constant for water (Kw). What is the value of Kw at 25˚C?
In most solutions containing a strong or weak acid, the autoionization of water can be neglected when calculating [H3O+]. Explain why this is so.
Calculate the pH of each of the following solutions.c. pure H2O
At 50 oC, the ion-product constant for H2O has the value Kw = 5.48 x 10-14.What is the pH of pure water at 50 oC?
Calculate the pH of each of the following solutions.c. pure H2O
What is the OH- concentration in an aqueous solution at 25oC in which [H3O+]=1.4×10−6 M ?
In humans, blood pH is maintained within a narrow range: acidosis occurs if the blood pH is below 7.35, and alkalosis occurs if the pH is above 7.45. Given that the p Kw of blood is 13.63 at 37°C (body temperature), what is the normal range of [H3O+] and of [OH−] in blood?
The disinfectant phenol, C6H5OH, has a pKa of 10.0 in water, but 14.4 in methanol.(d) Write an expression for the autoionization constant of methanol.
Like all equilibrium constants, the value of Kw depends on temperature. At body temperature (37oC), Kw = 2.4 x 10-14. What is the [H3O+] in pure water at body temperature?
Like all equilibrium constants, the value of Kw depends on temperature. At body temperature (37oC), Kw = 2.4 x 10-14. What is pH of pure water at body temperature?
The value of Kw increases with increasing temperature. Is the autoionization of water endothermic or exothermic?
Seashells are mostly calcium carbonate, which reacts with H 3O+ according to the equation CaCO3(s) + H3O+(aq) ⇌ Ca2+(aq) + HCO3−(aq) + H2O(l)If Kw increases at higher pressure, will seashells dissolve more rapidly near the surface of the ocean or at great depths? Explain.
Papaverine hydrochloride (abbreviated papH+Cl-; molar mass = 378.85 g/mol) is a drug that belongs to a group of medicines called vasodilators, which cause blood vessels to expand, thereby increasing blood flow. This drug is the conjugate acid of the weak base papaverine (abbreviated pap; Kb = 8.33 X 10 -9 at 35.0°C). Calculate the pH of a 30.0-mg/mL aqueous dose of papH+Cl- prepared at 35.0°C. K w at 35.0°C is 2.1 X 10 -14.
Calculate [H3O+] at 25˚C for each solution and determine whether the solution is acidic, basic, or neutral.(a) [OH–] = 1.5 x 10–2 M(b) [OH–] = 1.0 x 10–7 M(c) [OH–] = 8.2 x 10–10 M
Liquid ammonia autoionizes like water:2NH3(l)⟶NH4+(am) + NH2−(am)where (am) represents solvation by NH3.(d) At the boiling point of ammonia (−33°C), Kam = 5.1 x 10−27. Calculate [NH4+] at this temperature.
Liquid ammonia autoionizes like water:2NH3(l) ⟶ NH4+(am) + NH2−(am)where (am) represents solvation by NH3.(e) Pure sulfuric acid also autoionizes. Write the ion-product constant expression,  Ksulf, and find the concentration of the conjugate base at 20°C (Ksulf = 2.7 x 10−4 at 20°C).
If Kw = 1.139×10−15 at 0°C and 5.474×10−14 at 50°C, find [H3O+] and pH of water at 0°C and 50°C.
The autoionization constant for heavy water (deuterium oxide, D 2O) is 3.64×10−16 at 0°C and 7.89×10−15 at 50°C. Find [D 3O+] and pD of heavy water at 0°C and 50°C.
(a) If Kw = 1.139×10−15 at 0°C and 5.474×10−14 at 50°C, find [H3O+] and pH of water at 0°C and 50°C.(b) The autoionization constant for heavy water (deuterium oxide, D2O) is 3.64×10−16 at 0°C and 7.89×10−15 at 50°C. Find [D3O+] and pD of heavy water at 0°C and 50°C.(c) Suggest a reason for these differences.
Values of Kw as a function of temperature are as follows:a. Is the autoionization of water exothermic or endothermic?
Values of Kw as a function of temperature are as follows:b. Calculate [H +] and [OH -] in a neutral solution at 50.ºC.
Is the self ionization of water endothermic or exothermic? The ionization constant for water (Kw) is 2.9 × 10−14 at 40 °C and 9.3 × 10−14 at 60 °C.
Explain why a sample of pure water at 40 °C is neutral even though [H 3O+] = 1.7 × 10−7 M. Kw is 2.9 × 10−14 at 40 °C.
At 40.ºC the value of Kw is 2.92 x 10 -14.a. Calculate the [H +] and [OH -] in pure water at 40.ºC.
The ionization constant for water (Kw) is 2.9 × 10−14 at 40 °C. Calculate [H3O+], [OH−], pH, and pOH for pure water at 40 °C.
The ionization constant for water (Kw) is 9.311 × 10−14 at 60 °C. Calculate [H3O+], [OH−], pH, and pOH for pure water at 60 °C.
At 40.ºC the value of Kw is 2.92 x 10 -14.b. What is the pH of pure water at 40.ºC?
At 40.ºC the value of Kw is 2.92 x 10 -14.c. If the hydroxide ion concentration in a solution is 0.10 M, what is the pH at 40.ºC?
Use the following table to help order the following acids from strongest to weakest.HNO3, H2O, NH4+, C5H5NH+
Use the following table to help answer the following question.a. Which is the stronger acid, HClO4 or C6H5NH3+?
Use the following table to help answer the following question.b. Which is the stronger acid, H2O or C6H5NH3+?
Use the following table to help answer the following question.c. Which is the stronger acid, C6H5NH3+ or CH3NH3+?
Use the following figure to determine whether K c > 1 for(a) HCl + NH3 ⥫⥬ NH4+ + Cl−
Use the following figure to determine whether K c > 1 for(b) H2SO3 + NH3 ⥫⥬ HSO3− + NH4+
Use the following figure to determine whether K c > 1 for(a) OH− + HS− ⥫⥬ H2O + S2−
Use the following figure to determine whether K c > 1 for(b) HCN + HCO3− ⥫⥬ H2CO3 + CN−
Use the following figure to determine whether K c < 1 for(a) NH4+ + HPO42− ⥫⥬ NH3 + H2PO4−
Use the following figure to determine whether K c < 1 for(b) HSO3− + HS− ⥫⥬ H2SO3 + S2−
Use the following figure to determine whether K c < 1 for(a) H2PO4− + F− ⥫⥬ HPO42− + HF
Use the following figure to determine whether K c < 1 for(b) CH3COO− + HSO4− ⥫⥬ CH3COOH + SO42−
The following scene represent three weak acid HA (where A = X, Y, or Z) dissolved in water (H2O is not shown):(a) Rank the acids in order of increasing K a.
The following scene represent three weak acid HA (where A = X, Y, or Z) dissolved in water (H2O is not shown):(b) Rank the acids in order of increasing pK a.
For solution of the same concentration, as acid strength increases, indicate what happen to the following (increase, decrease, or doesn’t change).e. Ka
Consider a 0.60-M solution of HC 3H5O3, lactic acid (K a = 1.4 X 10 -4).a. Which of the following are major species in the solution?i. HC3H5O3ii. C3H5O3-iii. H+iv. H2Ov. OH-
Consider a 0.67-M solution of C 2H5NH2 (Kb = 5.6 X 10 -4).a. Which of the following are major species in the solution?i. C2H5NH2ii. H+iii. OH-iv. H2O v. C2H5NH3+
Arrange the following 0.10 M solutions in order from most acidic to most basic. See Appendix 5 for Ka and Kb values.        CaBr 2, KNO2, HClO4, HNO2, HONH3ClO4
The Kb values for ammonia and methylamine are 1.8 X 10 -5 and 4.4 X 10 -4, respectively. Which is the stronger acid, NH4+ or CH3NH3+?
Use Table 13‑2 to order the following from the strongest to the weakest acid.HClO2, H2O, NH4+, HClO4
Using the Ka value of 1.4 × 10−5, place Al(H2 O)6 3+ in the correct location in the following Figure.
You may need Table 13‑2 to answer the following questions.a. Which is the stronger acid, HCl or H2O?
You may need Table 13‑2 to answer the following questions.b. Which is the stronger acid, H2O or HNO2?
You may need Table 13‑2 to answer the following questions.c. Which is the stronger acid, HCN or HOC6H5?
Use Appendix C to rank the following in order of increasing acid strength: HIO  3, HI, CH3COOH, HF.
Use Appendix C to rank the following in order of decreasing acid strength: HClO, HCl, HCN, HNO2.
Consider these two acids and their Ka values:HF Ka = 3.5 x 10-4HCIO Ka = 2.9 x 10-8Which acid is stronger?
The beakers on the facing page depict the aqueous dissociations of weak acids HA (blue and green) and HB (blue and yellow); solvent molecules are omitted for clarity. If the HA solution is 0.50 L, and the HB solution is 0.25 L, and each particle represents 0.010 mol, find the Ka of each acid. Which acid, if either, is stronger?
Given that the Ka for acetic acid is 1.8x10-5 and the Ka for hypochlorous acid is 3.0x10-8, which is the stronger acid?
Given that Kb for ammonia is 1.8x10-5 and that for hydroxylamine is 1.1x10-8, which is the stronger acid, the ammonium ion or the hydroxylammonium ion?
What is the kb of water?
Formic acid has a pKa of 3.75. What is the ratio of concentrations of formate (the conjugate base) to formic acid (the conjugate acid) at pH 8.25?A) 32,000B) 10,000C) 100,000D) 3,200E) none of these
Rank the basicity of the amine groups in these amino acids according to their expected pKb values.
The pKa of methanol (CH3OH) is 15.5 and the pKa of ammonia (NH3) is 36. Which is a stronger base CH3O- or NH2-? Briefly explain your answer.
Rank these acids according to their expected p Ka values. From highest to lowest
Rank these acids according to their expected p Ka values.
Calculate the value for the equilibrium constant for the following aqueous reaction.a. NH3 + H3O+ ⇌ NH4+ + H2O
Calculate the value for the equilibrium constant for the following aqueous reaction.b. NO2- + H3O+ ⇌ HNO2 + H2O
Calculate the value for the equilibrium constant for the following aqueous reaction.c. NH4+ + OH- ⇌ NH3 + H2O
Calculate the value for the equilibrium constant for the following aqueous reaction.d. HNO2 + OH- ⇌ H2O + NO2-
 K a for acetic acid is 1.8 x 10-5. What is the first digit of the pK a value for acetic acid?
What is the Ka of the 2-hydroxyethylammonium ion, HOCH2CH2NH3+ (pKb of HOCH2CH2NH2 = 4.49)?
(b) What is the pKa of the hydrazinium ion, H2N—NH3+ (Kb of hydrazine = 8.5 x 10−7)?
A 1.000 m solution of chloroacetic acid (ClCH 2COOH) freezes at −1.93°C. Find the K a of chloroacetic acid. (Assume that the molarities equal the molalities.)
Use the following table to help order the following bases from strongest to weakest. NO3-, H2O, NH3, C5H5N
Use the following table to help answer the following question.a. Which is the stronger base, ClO4- or C6H5NH2?
Both HF and HCN ionize in water to a limited extent. Which of the conjugate bases, F − or CN−, is the stronger base? see the following Table
Use the following table to help answer the following question.b. Which is the stronger base, H 2O or C6H5NH2?
Use the following table to help answer the following question.c. Which is the stronger base, OH - or C6H5NH2?
Use the following table to help answer the following question.d. Which is the stronger base, C6H5NH2 or CH3NH2?
Phenol, (C6H5OH), has a Ka of 1.3 x 10-10. Is the phenolate ion a weaker or stronger base than water?
The following scene represent three weak acid HA (where A = X, Y, or Z) dissolved in water (H2O is not shown):(c) Rank the conjugate bases in order of increasing pK b.
Consider the given acid ionization constants. Identify the strongest conjugate base.Acid Ka HNO2(aq)4.6×10−4HCHO2(aq)1.8×10−4HClO(aq)2.9×10−8HCN(aq)4.9×10−10
The disinfectant phenol, C6H5OH, has a pKa of 10.0 in water, but 14.4 in methanol.(a) Why are the values different?
The disinfectant phenol, C6H5OH, has a pKa of 10.0 in water, but 14.4 in methanol.(b) Is methanol a stronger or weaker base than water?
Given that the Ka value for acetic acid is 1.8X 10 -5 and the Ka value for hypochlorous acid is 3.5 X 10-8, which is the stronger base, OCl - or C2H3O2-?
Use Table 13‑2 to order the following from the strongest to the weakest base.ClO2-, H2O, NH3, ClO4-
You may need Table 13‑2 to answer the following questions.a. Which is the stronger base, Cl2 or H2O?
You may need Table 13‑2 to answer the following questions.b. Which is the stronger base, H2O or NO2-?
You may need Table 13‑2 to answer the following questions.c. Which is the stronger base, CN - or OC6H5 -?
Given that the Ka for acetic acid is 1.8x10-5 and the Ka for hypochlorous acid is 3.0x10-8, which is the stronger base, the acetate ion or the hypochlorite ion?
Given that Kb for ammonia is 1.8x10-5 and that for hydroxylamine is 1.1x10-8, which is the stronger base?
Codeine (C18H21NO3) is a derivative of morphine that is used as an analgesic, narcotic, or antitussive. It was once commonly used in cough syrups but is now available only by prescription because of its addictive properties. If the pH of a 1.7 X 10-3-M solution of codeine is 9.59, calculate Kb.
Phenol, (C6H5OH), has a Ka of 1.3 x 10-10. Calculate Kb for the phenolate ion.
Find the pH of 0.150 M NaCN solution. For HCN, Ka = 4.9 x 10-10.
Calculate the ionization constant for the following acid or base from the ionization constant of its conjugate base or conjugate acid:(a) F−
Calculate the ionization constant for the following acid or base from the ionization constant of its conjugate base or conjugate acid:(b) NH4 +
Calculate the ionization constant for the following acid or base from the ionization constant of its conjugate base or conjugate acid:(c) AsO4 3−
Calculate the ionization constant for the following acid or base from the ionization constant of its conjugate base or conjugate acid:(d) (CH3)2 NH2 +
Calculate the ionization constant for the following acid or base from the ionization constant of its conjugate base or conjugate acid:(e) NO2 −
Calculate the ionization constant for the following acid or base from the ionization constant of its conjugate base or conjugate acid:(f) HC2 O4 − (as a base)
Calculate the ionization constant for the following acid or base from the ionization constant of its conjugate base or conjugate acid: (a) HTe− (as a base)
Calculate the ionization constant for the following acid or base from the ionization constant of its conjugate base or conjugate acid: (b) (CH3)3 NH+
Calculate the ionization constant for the following acid or base from the ionization constant of its conjugate base or conjugate acid: (c) HAsO4 3− (as a base)
Calculate the ionization constant for the following acid or base from the ionization constant of its conjugate base or conjugate acid: (d) HO2 − (as a base)
Calculate the ionization constant for the following acid or base from the ionization constant of its conjugate base or conjugate acid: (e) C6 H5 NH3 +
Calculate the ionization constant for the following acid or base from the ionization constant of its conjugate base or conjugate acid: (f) HSO3 − (as a base)
Given that the Ka for acetic acid is 1.8x10-5 and the Ka for hypochlorous acid is 3.0x10-8, calculate the Kb value for CH3COO-.
Given that the Ka for acetic acid is 1.8x10-5 and the Ka for hypochlorous acid is 3.0x10-8, calculate the Kb value for ClO-.
Given that Kb for ammonia is 1.8x10-5 and that for hydroxylamine is 1.1x10-8, calculate Ka value for NH4+.
Given that Kb for ammonia is 1.8x10-5 and that for hydroxylamine is 1.1x10-8, calculate Ka value for H3NOH+.
What is the ionization constant at 25 °C for the weak acid CH 3 NH3 +, the conjugate acid of the weak base CH3NH2, Kb = 4.4 × 10−4.
What is the ionization constant at 25 °C for the weak acid (CH 3)2 NH2 +, the conjugate acid of the weak base (CH3)2NH, Kb = 5.9 × 10−4?
The pH of a 1.00 M solution of urea, a weak organic base, is 7.050.Calculate the Ka of protonated urea.
Given that Kb for (CH3)3N is 6.3 × 10-5 at 25°C, what is the value of Ka for (CH3)3NH+ at 25 °C?
Given that Ka for HClO is 4.0 x 10-8 at 25°C, What is the value of Kb for ClO- at 25°C? Kb =____? 
Complete the Kw expression for the autoionization of water.Kw = 1.00 x 10-14 =  
At 0 degrees C, the ion product constant of water is 1.2x10 –15. The pH of pure water at this temperature is:6.887.007.467.56
What is the Kw of pure water at 50 degrees C, if the pH is 6.630?
An acid with a low pKa: (a) is a weak acid (b) is a strong acid (c) has a weak conjugate base (d) both b and c  
Given that Ka for HIO is 3.2 × 10-11 at 25°C, what is the value of Kb for IO– at 25°C?
A monoprotic acid, HA, is dissolved in water HA ⇌ H+ + A- The equilibrium concentrations of the reactants and products are HA 0.150 M [H+] = 3.00 × 10-4 M[A-] = 3.00 × 10-4 M Calculate the value of pka for the acid HA. 
The Ka of HCN is 6.2 x 10 -10. What is the Kb value for CN - at 25°C
Given the following acids and Ka values: HClO4                  HOAc                     HCN                    HF 1 x 107                 1.76 x 10-5             4.93 x 10-10         3.53 x 10-4 What is the order of increasing base strength?
The Kb for a weak base is 6.7 times 10 -13. What will be the Ka for its conjugate acid? 
For the simple hydrides, MHn, pKa values decrease in the order: 
The Kw for water at 0°C is 0.12 x 10-14. Calculate the pH of a neutral aqueous solution at 0°C. ls a pH = 7.25 solution acidic, basic, or neutral at 0°C? 
Given that Ka for HF is 6.3 x 10 at 25 C, what is the value of Kb for F at 25°C?
What does it mean to say that water autoionizes? Water will cause many ionic compounds to dissociate without additional input of energy. Water is polar, like an ion is polar. Therefore it is autoionic. Water is a good conductor of electricity, and when it conducts, it ionizes. A water molecule can donate a proton to another water molecule, forming H 2O+ and OH- in solution. 
Complete the table below. Round each of your entries to 2 significant digits. You may assume the temperature is 25°C. 
What is the Ka reaction of HCN?The Ka of HCN is 6.2 x 10-10. What is the Kb, value for CN- at 25°C? Kb = 
Which of the following organic compounds has the strongest conjugate base? 
Given that Ka for HCN is 6.2 x 10-10 at 25°C, what is the value of Kb for CN- at 25°C? Given that Kb for C6H5NH2 is 1.7 x 10-9 at 25°C, what is the value of Ka for C6H5NH3+ at 25°C?
a. Given that Ka for HCN is 6.2x10-10 at 25°c, what is the value of Kb for CN- at 25°c?b. Given that Kb for NH3 is 1.8x10-5 at 25°c, what is the value of Ka for NH4+ at 25°c?
At 25°C, what is the hydroxide ion concentration, [OH-], in an aqueous solution with a hydrogen ion concentration of [H+] = 2.4 x 10-9 M? 
The pka of acetic acid is 4.76 and the pka of trichloroacetic acid, which is used to remove warts, is 0.7. Calculate the dissociation constant of each acid. Which is the stronger acid?