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
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Ch.4 - Chemical Quantities & Aqueous Reactions
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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
Jules Bruno

Weak bases

In this guide, we’ll talk about how to calculate the pH of a weak base solution. First of all, a weak base, all weak bases in fact, have a base association constant or Kb less than 1. 

Calculating pH of a weak base solution

In order to find the pH of a weak base solution, you’re going to have to set up an ICE chart. Remember, ICE stands for Initial Change Equilibrium. The units inside the ICE chart for the weak base will be in molarity. Remember, that’s just moles over liters. The initial amounts of your products will be zero. Then remember the changes we lose reactants in order to make products. Here we’re going to have -x from our reactant and our products are being formed so that’s +x and +x. We’re going to say here that equilibrium is just initial minus the change here so that’s 0.025 - x. Here this is 0 + x, and 0 + x but we just ignore the zero portion. 

calculating pH using ICE chart

Setting up our equilibrium expression, we know that Kb will equal my products over reactants. Here, both my products at equilibrium are equal to x. If they’re multiplying each other, that’s going to give me me x2 on top. For the weak base, it will be on the bottom. Initial concentration minus x. Here’s the thing. At this point, we have to debate whether we keep this -x or ignore it. If we keep it, then we’ll have to do the quadratic formula in order to solve for x on top. Once we do, we can figure out the pOH. If we could ignore the -x, then we will not have to do the quadratic formula and then our equation becomes a lot easier. 

How exactly do we figure out if we can ignore it or not? To do it, we do the 5% approximation method. What you’re going to do here is you’re going to take your initial concentration of your weak base divided by your base association constant Kb. If you get an answer greater than 500, then you could ignore this -x. Therefore, you could ignore the quadratic formula. Again, always use the 5% approximation with weak base solution to see if you could ignore the -x to avoid the quadratic formula. 

When we solve for x here, x will represent the concentration of hydroxide ion concentration. Therefore, when you take the negative log of that concentration, that will give you pOH. Remember, if you know pOH, you know pH because pH will just be 14 - pOH. This is the basic set up for a weak base solution and how we calculate the pH of that solution. 

solving with the 5% approximation method


Related weak bases practice problems


Jules Bruno

Jules felt a void in his life after his English degree from Duke, so he started tutoring in 2007 and got a B.S. in Chemistry from FIU. He’s exceptionally skilled at making concepts dead simple and helping students in covalent bonds of knowledge.


Additional Problems
Answer the following questions dealing with the weak base ammonia.  A. Ammonia, NH3, is incredibly soluble in water. Why? B. Calculate the molarity and molality of a solution that is 30.0 g NH 3 in 70.0 g water. The density of that solution is 0.982 g/mL.          C. Consider the following solutions: 0.1 M NH 3(aq) and 0.1 M NaOH(aq). Which solution has the highest osmotic pressure? ____________________________ Why?   Which solution has the highest boiling point? ____________________________  Why?   Which solution has the highest pH? ____________________________ Why?     D. Calculate the pH of 0.1 M NH 3(aq). Kb of NH3 is 1.8 x 10-5 .          
When ammonium chloride is added to NH 3(aq),  1. the Kb increases. 2. the pH of the solution increases. 3. the pH of the solution decreases. 4. the pH of the solution does not change. 5. the equilibrium concentration of NH 3(aq) decreases
An unknown weak base has an initial concentration of 0.23 M. What is the pH of the solution if the weak base also has a pKb of 5.18. 
An unknown base, A-, with an initial concentration of 0.330 M has a percent ionization of 2.17%. What is the pH of the solution? 
Determine the pH of solution created by dissolving 0.748 grams of strychnine, C21H22N2O2, {MW = 334.45 g/mol) in 592 mL of solution. A. 4.08 B. 8.17 C. 9.80 D. 9.92 E. 5.83
Calculate the percent ionization (protonation) of a 0.342 M solution of an unknown base. Kb = 1.9 x 10-5 for this base. A. 0.075 % B. 0.086 % C. 0.86 % D. 0.37 % E. 0.75 %
Given the concentration of a weak base solution and a K b value for the weak base, what is the correct procedure to determine the pH of the solution? A.  Set concentration of weak base equal to [OH -], convert to [H3O+] and solve for pH B.  Convert Kb to Ka and use a table to find the equilibrium concentration of [H 3O+] and solve for pH C.  Convert Kb to Ka and use pH = pKa + log(base / acid) D.  Use a table to find the equilibrium concentration of the conjugate acid which is equal to [H  3O+] and solve for pH E.  Use a table to find the equilibrium concentration of [OH -], convert to [H3O+] and solve for pH
Determine the pH of a 0.100 M solution of NaBrO where K a (HBrO) = 2.8 X 10  -9. A.  3.22      B.  4.78      C.  9.22      D. 10.78      E.  13.00
Determine the pH of a 0.188 M NH 3 solution at 25°C. The Kb of NH3 is 1.76 x 10-5. A) 5.480 B) 2.740 C) 8.520 D) 11.260 E) 13.656
Calculate the pH of a 0.10 M solution of hydrazine, N2H4. Kb for hydrazine is 1.3×10−6. Express your answer numerically using two decimal places.
A 0.80 M solution of an unknown base has pOH of 3.50. What is the pKb?  a) less than 1 b) 1.23 c) 7.10 d) 5.55 e) 6.90
What is the pH of a 0.23 M pyridine (C 5H5N) solution? The base dissociation constant of pyridine is 1.7 x 10 -9.
What is the pH of a 0.25 M solution of KCOOH? A. 0.60  B. 4.35 C. 5.43 D. 8.57 E. 9.65
Calculate the pH of 0.010 M sodium hypochlorite, NaClO, given that Ka = 3.0 x 10 -8 for hypochlorous acid, HClO. 
Calculate the pH of 0.030 M NaNO 2. The Ka of HNO2 is 4.6 x 10 -4.
An unknown weak base has an initial concentration of 0.320 M with a pOH of 9.07. Calculate its equilibrium base constant. 
Calculate the pH of 0.250 M LiF. The Ka of HF is 3.5 x 10  -4.
Answer the following questions.  i) Calculate the pH of a 0.20 M solution of KCN.             ii) Calculate the pH of a 0.20 M solution of NH4Cl.
What mass of sodium nitrite must be added to 350.0 mL of water to give a solution with pH = 8.40? Ka of HNO2 = 5.6 x 10 -4 A) 68 g B) 1.7 x 10-4 g C) 0.039 g D) 8.5 g E) 24 g
Calculate the pH of a 0.021 M NaCN solution. Ka of HCN = 4.9 x 10 -10 A) 1.68 B) 3.18 C) 5.49 D) 7.00 E) 10.82
What is the pH of a 0.050 M triethylamine, (C 2H5)3N, solution? Kb for triethylamine is 5.3 x 10-4. A) 11.69 B) 8.68 C) 5.32 D) 2.31 E) < 2.0
Cocaine is a weak organic base whose molecular formula is C17H21NO4. An aqueous solution of cocaine was found to have a pH of 8.53 and an osmotic pressure of 52.7 torr at 15 oC.Calculate Kb for cocaine.
A solution of 0.23 mol of the chloride salt of protonated quinine (QH+), a weak organic base, in 1.0 L of solution has pH=4.58.Find the Kb of quinine (Q).
A 0.140 M solution of a weak base has a pH of 11.25.Determine Kb for the base.
Calculate the concentration of all species in a 0.16 M KF solution.
Determine the pH of each of the following solutions.0.250 M CH3 NH3 I
Determine the pH of each of the following solutions.0.322 M KC6 H5 O
Determine the pH of each of the following two-component solutions.0.113 M in NaCl and 9.53×10−2 M in KF
Calculate the pH of a solution prepared from 0.201 mol of NH4CN and enough water to make 1.00 L of solution.
Calculate the pH of each of the following solutions (Ka and Kb values are given in Appendix D in the textbook).0.121 M pyridine (C5 H5 N).
Determine the pH of each of the following solutions (Ka and Kb values are given in Appendix D in the textbook).9.5×10−2 M hydroxylamine.
Solve an equilibrium problem (using an ICE table) to calculate the pH of each of the following solutions.0.16 M CH3 NH2
Determine pH of a 0.18 M ammonia solution.
Determine the pH of each of the following solutions.0.16 M NaC2 H3 O2
Butyric acid is responsible for the foul smell of rancid butter. The pKa of butyric acid is 4.84.Calculate the pH of a 5.0×10−2 M solution of sodium butyrate.
Determine the pH of each of the following solutions.0.21 M KCHO2
Calculate the [OH−] concentration in a 0.5 M solution of potassium fluoride (KF). Ka for HF is 7.2 × 10−4.1. 6.94 × 10−12 M2. 0.5 M3. 6.0 × 10−6 M4. 3.6 × 10−11 M5. 2.64 x 10-6 M
Calculate the pH of a 0.30 M solution of sodium acetate (NaCH3COO) given that the Ka of acetic acid (CH3COOH) is 1.8 x 10 - 5.
Determine the pH of a 0.188 M NH 3 solution at 25°C. The Kb of NH3 is 1.76 × 10-5.  
Determine the pH of a 0.22M NaF solution at 25°C. The K a of HF is 3.5 x 10 -5.a. 10.20b. 5.10c. 8.90d. 11.44e. 2.56
Calculate the pH of a 1.60 M KBrO solution. Ka for hypobromous acid, HBrO, is 2.0 × 10-9.
What is the pH of a 0.593 M solution ethylamine, C 2H5NH2, solution?A. 1.74B. 3.48C. 10.52D. 12.26E. 13.77
Find the pH of a 0.250 M solution of NaC2H3O2. (The Ka value of HC2H3O2 is 1.80×10-5).
Calculate the pH of a 0.021 M NaCN solution.A. 3.18B. 8.51C. 5.94D. 10.82E. 12.32
A certain weak base has a Kb of 8.60 × 10-7. What concentration of this base will produce a pH of 10.27?
Determine the pH of a 0.35 M aqueous solution of CH 3NH 2 (methylamine). The K b of methylamine is 4.4 × 10 −4.     A) 13.24      B) 3.86      C) 10.00      D) 12.09      E) 1.96
A beaker left on a lab bench contains 0.0926 M solution of an unknown weak base solution. Using a pH meter, a student measures the pH of this solution and determines it to be 11.48. Determine the base dissociation constant (Kb) of the base.A. 9.12 x 10-6B. 9.85 x 10-5C. 1.02 x 10-4D. 3.58 x 10-11E. 1.08 x10-13
Determine the pH of a 0.15 M aqueous solution of KF. For HF,  Ka = 7.0 × 10−4.A) 5.85            B) 12.01          C) 8.17            D) 6.68            E) 2.32
Determine the pH of a 0.15 M solution of NaBrO. K a (HBrO) = 2.8 * 10 -9A) 2.72B) 4.69C) 9.31D) 10.86E) 11.28
A 0.100 M solution of ethylamine (C2H5NH2) has a pH of 11.87. Calculate the Kb for ethylamine.
a. NH3 is a weak base (Kb = 1.8 × 10–5) and so the salt NH4Cl acts as a weak acid. What is the pH of a solution that is 0.030M in NH4Cl at 25°C?b. HClO is a weak acid (Ka = 4.0 × 10–8) and so the salt NaClO acts as a weak base. What is the pH of a solution that is 0.045 M in NaClO at 25°C?
Calculate the pH of a 0.234 M NaHCO3 solution. Look up the appropriate Ka or Kb value.
Determine the pH of a 0.22 M NaF solution at 25°C. The salt completely dissociates into Na + (aq) and F - (aq), and the Na + (aq) ion does not have acid or base properties. The K a of HF is 3.5 × 10-5.A) 10.20B) 5.10C) 8.90D) 11.44E) 2.56
Ammonia, NH3, is a weak base with a K b value of 1.8 x 10 -5.a. What is the pH of a 0.450 M ammonia solution? Express your answer numerically to two decimal places.b. What is the percent ionization of ammonia at this concentration? Express the percentage numerically to three significant figures.
Caffeine (C8H10N4O2) is a weak base with a pKb of 10.4. Calculate the pH of a solution containing 455 mg/L of caffeine.
Morphine is a weak base. A 0.150 M solution of morphine has a pH of 10.5. What is the Kb for morphine.
Calculate the pH and concentrations of CH3NH2 and CH3NH3+ in a 0.0279 M methylamine (CH3NH2) solution. The Kb of CH3NH2 = 4.47x 10 - 4.pH = ______(CH3,NH2) = ________(CH3,NH3+) = ________
Calculate the pH for a 0.20 M pyridine (C 5H5N) solution. Kb = 1.7 × 10-9
If the Kb of a weak base is 6.2 × 10-6, what is the pH of a 0.39 M solution of this base?
Codeine C18H21NO3 is a weak organic base. A 5.0 x 10-3 M solution of codeine has a pH of 9.95. Calculate the value of Kb for this substance. What is the pKb for this base?
Find the [OH-] and pH of a 0.33 M methylamine (CH 3NH2) aqueous solution.Kb (CH3NH2) = 4.4 × 10-4.
Sodium azide (NaN3) is sometimes added to water to kill bacteria. Calculate the concentration of all species in a 0.021 M solution of NaN3. The Ka value for hydrazoic acid (HN 3) is  2.5 x 10 -5
What is the percent ionization of 0.50 M NH 3 (aq) solution? The Kb of NH3 is         1.8x10–5a) 0.50 %b) 0.60 %c) 0.70 %d) 0.80 %e) 0.90 %
Ka HNO2 = 7.1 x 10-4 and Pka HNO2 = 3.15 a) Calculate the pH of 0.74 M KNO2. b) What is the concentration of HNO2 in the above solution?
Morphine is a weak base. A 0.150 M  solution of morphine has a pH of 10.5.What is Kb for morphine?
The compound dimethylamine, (CH3)2NH, is a weak base when dissolved in water. Write the Kb expression for the weak base equilibrium that occurs in an aqueous solution of dimethylamine:
Write the reaction and the corresponding K b equilibrium expression for the following substance acting as base in water.a. NH3
Write the reaction and the corresponding K b equilibrium expression for the following substance acting as base in water.b. C5H5N
Write the reaction and the corresponding K b equilibrium expression for the following substance acting as base in water.a. aniline, C6H5NH2
Write the reaction and the corresponding K b equilibrium expression for the following substance acting as base in water.b. dimethylamine, (CH3)2NH
The pH of a 0.016-M aqueous solution of p-toluidine (CH 3C6H4NH2) is 8.60. Calculate Kb.
From the equilibrium concentration given, calculate K a for the weak acid and K b for the weak base.(b) ClO−: [OH−] = 4.0 × 10−4 M;      [HClO]        = 2.38 × 10  −5 M;       [ClO −]         = 0.273 M;
From the equilibrium concentration given, calculate K a for the weak acid and K b for the weak base.(a) NH3: [OH −] = 3.1 × 10 −3 M;     [NH 4 +] = 3.1 × 10 −3 M;     [NH 3] = 0.533 M;
From the equilibrium concentration given, calculate K a for the weak acid and K b for the weak base.(c) (CH3)3N: [(CH3)3N] = 0.25 M;[(CH3)3NH+] = 4.3 × 10−3 M;[OH−] = 4.3 × 10−3 M;
Determine Kb for the nitrite ion, NO 2−. In a 0.10-M solution this base is 0.0015% ionized.
Write balanced equation and K b expression for the Brønsted-Lowry base in water:(a) Pyridine, C5H5N
Write balanced equation and K b expression for this Brønsted-Lowry base in water:(a) Hydroxylamine, HO—NH2
Write balanced equation and K b expression for the Brønsted-Lowry base in water:(b) CO32−
Write balanced equation and K b expression for the Brønsted-Lowry base in water:(a) Benzoate ion, C6H5COO−
Write balanced equation and K b expression for the Brønsted-Lowry base in water:(b) (CH3)3N
Write the chemical equation and the Kb expression for the ionization of each of the following bases in aqueous solution.(CH3)2NH
Write the chemical equation and the Kb expression for the ionization of each of the following bases in aqueous solution.CO32-
Write balanced equation and K b expression for this Brønsted-Lowry base in water:(b) HPO42−
Write the chemical equation and the Kb expression for the ionization of each of the following bases in aqueous solution.CHO2-
Write balanced equation and Kb expression for this Brønsted-Lowry base in water:(a) Guanidine, (H2N)2C=NH (the double-bonded N is more basic)
Write balanced equation and Kb expression for this Brønsted-Lowry base in water:(b) Acetylide ion, HC≡C−
Write the chemical equation and the Kb expression for the reaction of each of the following bases with water.C3H7NH2
Write the chemical equation and the Kb expression for the reaction of each of the following bases with water.HPO42-
Write the chemical equation and the Kb expression for the reaction of each of the following bases with water.C6H5CO2-
(a) What is the Kb of the acetate ion?
An unknown salt is either NaCN, NaC2H3O2, NaF, NaCl, or NaOCl. When 0.100 mole of the salt is dissolved in 1.00 L of solution, the pH of the solution is 8.07. What is the identity of the salt?
(a) What is the Kb of the benzoate ion, C6H5COO−?
Consider a solution of an unknown salt having the general formula BHCl, where B is one of the weak bases in the following table. A 0.10-M solution of the unknown salt has a pH of 5.82. What is the actual formula of the salt?
(a) What is the pKb of ClO2−?
(a) What is the pKb of NO2−?
Codeine (C18H21NO3) is a weak organic base. A 5.0x10-3 M solution of codeine has a pH of 9.95. Calculate the value of Kb for this substance.
Codeine (C18H21NO3) is a weak organic base. A 5.0x10-3 M solution of codeine has a pH of 9.95. What is the pKb for this base?
The pH of a 0.10-M solution of caffeine is 11.16. Determine K b for caffeine from these data: C8 H10 N4 O2(aq) + H2 O(l) ⇌ C8 H10 N4 O2 H+(aq) + OH−(aq)
The pH of a solution of household ammonia, a 0.950 M solution of NH 3, is 11.612. Determine Kb for NH3 from these data.
The ion HTe− is an amphiprotic specie; it can act as either an acid or a base.(a) What is Ka for the acid reaction of HTe − with H2O?
The ion HTe− is an amphiprotic specie; it can act as either an acid or a base.(b) What is Kb for the reaction in which HTe− functions as a base in water?
Write equations showing how each of the following weak bases ionizes water to form OH–. Write the corresponding expression for Kb.NH3
Write equations showing how each of the following weak bases ionizes water to form OH–. Write the corresponding expression for Kb.HCO3–
Write equations showing how each of the following weak bases ionizes water to form OH–. Write the corresponding expression for Kb.CH3NH2
Write equations showing how each of the following weak bases ionizes water to form OH–. Write the corresponding expression for Kb.CO32–
Write equations showing how each of the following weak bases ionizes water to form OH–. Write the corresponding expression for Kb.C6H5NH2
Write equations showing how each of the following weak bases ionizes water to form OH–. Write the corresponding expression for Kb.C2H5NH2
Putrescine [NH2(CH2)4NH2], found in rotting animal tissue, is now known to be in all cells and essential for normal and abnormal (cancerous) growth. It also plays a key role in the formation of GABA, a neurotransmitter. A 0.10 M aqueous solution of putrescine has [OH−] = 2.1×10−3. What is the K b?
Aniline, C6H5NH2, is a weak base that dissociates in water. At 25 °Celsius, the base dissociation constant, Kb , for aniline is 4.3 x 10 -10.(A) Determine the hydroxide ion concentration and the percentage dissociation of a .150 molar solution of aniline at 25 °Celsius. 
Which of the following will increase the percent of NH 3 that is converted to the ammonium ion in water (Hint: Use LeChâtelier’s principle.)?(a) addition of NaOH(b) addition of HCl(c) addition of NH4Cl
What is the effect on the concentration of NO 2 −, HNO2, and OH− when the following is added to a solution of KNO2 in water? The equation for the equilibrium is: NO2 −(aq) + H2 O(l) ⇌ HNO2(aq) + OH−(aq)(a) HCl
Calculate the mass of HONH 2 required to dissolve in enough water to make 250.0 mL of solution having a pH of 10.00 (Kb = 1.1 X 10 -8).
Even though both NH3 and C6H5NH2 are weak base, NH3 is a much stronger acid than C6H5NH2. Which of the following is correct at equilibrium for a solution that is initially 0.10 M in NH3 and 0.10 M in C6H5NH2?(a) [OH−] = [NH4+](b) [NH4+] = [C6H5NH3+](c) [OH−] = [C6H5NH3+](d) [NH3] = [C6H5NH2](e) both a and b are correct
Nicotine, C10H14N2, is a base that will accept two protons (K1 = 7 × 10−7, K2 = 1.4 × 10−11). What is the concentration of each species present in a 0.050-M solution of nicotine?
Novocaine, C13H21O2N2Cl, is the salt of the base procaine and hydrochloric acid. The ionization constant for procaine is 7 × 10−6. Is a solution of novocaine acidic or basic? What are [H3O+], [OH−], and pH of a 2.0% solution by mass of novocaine, assuming that the density of the solution is 1.0 g/mL.
Household ammonia is a solution of the weak base NH 3 in water. List, in order of descending concentration, all of the ionic and molecular species present in a 1-M aqueous solution of this base.
Acrylic acid (CH 2=CHCO2H) is a precursor for many important plastics. Ka for acrylic acid is 5.6 X 10-5.b. Calculate the percent dissociation of a 0.10-M solution of acrylic acid.
Quinine (C20H24N2O2) is the most important alkaloid derived from cinchona bark. It is used as an antimalarial drug. For quinine, pK b1 = 5.1 and pK b2 = 9.7 (pK b = -log K b). Only 1 g quinine will dissolve in 1900.0 mL of solution. Calculate the pH of a saturated aqueous solution of quinine. Consider only the reaction Q + H2O ⇌ QH + + OH - described by pK b1, where Q = quinine.
What is the pH of a 0.65 M solution of pyridine, C5H5N? (The Kb value for pyridine is 1.7 x 10-9)
What are the major species present in a 0.150-M NH 3 solution? Calculate the [OH -] and the pH of this solution.
Order the following solutions from lowest to highest pH:0.10 M NaClO0.10 M KBr0.10 M NH4ClO4
For the reaction of hydrazine (N 2H4) in water, H2NNH2 (aq) + H2O(l) ⇌ H2NNH3+(aq) + OH -(aq)Kb is 3.0 X 10-6. Calculate the concentrations of all species and the pH of a 2.0-M solution of hydrazine in water.
Calculate [OH-], [H+], and the pH of 0.20 M solution of the following amine.a. triethylamine [(C2H5)3N, Kb = 4.0 X 10 -4]
Calculate [OH-], [H+], and the pH of 0.20 M solution of the following amine.b. hydroxylamine (HONH2, Kb = 1.1 X 10 -8)
Calculate [OH-], [H+], and the pH of 0.40 M solution of the following amine (the K  b values are found in the following table).a. aniline
Calculate the pH of a 0.20-M C 2H5NH2 solution (Kb = 5.6 X 10 -4).
Calculate the pH of a 0.050-M (C 2H5)2NH solution (Kb = 1.3 X 10 -3).
Calculate the pH of the following solution:b. 0.84 M C6H5NH3NO3 (Kb for C6H5NH2 = 3.8 X 10 -10)
Calculate the pH of the following solution:c. 0.57 M KC 7H5O2 (Ka for HC7H5O2 = 6.4 X 10 -5)
Calculate the pH of each of the following solutions.b. 0.100 M HONH3Cl
Solve an equilibrium problem (using an ICE table) to calculate the pH of each of the following solutions. (Ka(HF)=6.8 x 10-4)0.14 M NaF
Determine [OH-], [H+], and the pH of the following solution.a. 1.0 M KCl
Calculate the concentrations of all species present in a 0.25-M solution of ethylammonium chloride (C2H5NH3Cl).
Calculate the pH of the following solution.a. 0.10 M CH3NH3Cl
Tris(hydroxymethyl)aminomethane, known as TRIS or THAM, is a water-soluble base used in synthesizing surfactants and pharmaceuticals, as an emulsifying agent in cosmetics, and in cleaning mixtures for textiles and leather. In biomedical research, solutions of TRIS are used to maintain nearly constant pH for the study of enzymes and other cellular components. Given that the pKb is 5.91, calculate the pH of 0.075 M TRIS.
Calculate the pH of the following solution.a. 0.12 M KNO2
Calculate the pH of the following solution.c. 0.40 M NH 4ClO4
What is the pH of 0.070 M dimethylamine?
What is the pH of 0.12 M diethylamine?
What is the pH of 0.25 M ethanolamine?
What is the pH of 0.26 M aniline?
Amphetamine(C9H13N) is a weak base with a pK b of 4.2? Calculate the pH of a solution containing an amphetamine concentration of 205 mg/L.
Acetic acid has a Ka of 1.8×10−5, and ammonia has a K b of 1.8×10−5. Find [H3O+], [OH−], pH, and pOH for 0.240 M acetic acid
A 0.20-M sodium chlorobenzoate (NaC 7H4ClO2) solution has a pH of 8.65. Calculate the pH of a 0.20-M chlorobenzoic acid (HC7H4ClO2) solution.
Acetic acid has a Ka of 1.8×10−5, and ammonia has a Kb of 1.8×10−5. Find [H3O+], [OH−], pH, and pOH for 0.240 M ammonia.
(a) What is the pH of 0.150  M KCN?
(a) What is the pH of 0.100 M sodium phenolate, C 6H5ONa, the sodium salt of phenol?
(b) What is the pH of 0.15 M methylammonium bromide, CH 3NH3Br (Kb of CH3NH2 = 4.4 x 10−4)?
(a) What is the pH of 0.65 M potassium formate, HCOOK?
Determine the pH of a solution that is 0.135 M in CO32 -.
(a) What is the pH of 0.75 M NaF?
Determine the pOH of a solution that is 0.135 M in CO32 - .
Codeine (C18H21NO3) is a narcotic pain reliever that forms a salt with HCl. What is the pH of 0.050 M codeine hydrochloride (pKb of codeine = 5.80)?
Sodium stearate (C17H35COONa) is a major component of bar soap. The K a of the stearic acid is 1.3×10−5. What is the pH of 10.0 mL of a solution containing 0.42 g of sodium stearate?
Caffeine (C8 H10 N4 O2 ) is a weak base with a pKb of 10.4. Calculate the pH of a solution containing a caffeine concentration of 455 mg/L .
Calculate the pH of a 0.20 M solution of KCN at 25.0°C. Express the pH numerically using two decimal places. pH = Calculate the pH of a 0.20 M solution of NH4Br at 25.0°C. Express the pH numerically using two decimal places. pH =
Amphetamine (C9 H13 N) is a weak base with a pKb of 4.2. Calculate the pH of a solution containing an amphetamine concentration of 230 mg/L .
Consider the titration of a 26.0-mL sample of 0.175 M CH3NH2 with 0.155 M HBr. Determine each of the following.the initial pH
Calculate the percentage of pyridine (C 5H5N) that forms pyridinium ion, C5H5NH+, in a 0.10-M aqueous solution of pyridine (Kb = 1.7 X 10 -9).
Which of the following is the correct K b expression for the reaction below:B(aq) + H2O(l) ⇌ HB+(aq) + OH-(aq)A) Kb = [B][H2O]B) Kb = [HB+][OH-] / [B][H2O]C) Kb = [HB+][OH-] / [H2O]D) Kb = [HB+][OH-] / [B]E) Kb = [HB+][OH-]
Determine the pH of a 0.227 M C5H5N solution at 25.0°C. The Kb of C5H5N is 1.7 x 10-9.
A 0.100 M solution of ethylamine (C 2H5NH2) has a pH of 11.87. Calculate the K b for ethylamine.
Morphine is a weak base. A 0.150 M solution of morphine has a pH of 10.5.What is Kb for morphine?
The pH of 0.1 M C 4H9NH2(aq) (butylamine) aqueous solution was measured to be 12.04. What is the value of pKb of butylamine?1. 1.962. 2.933. 2.574. 0.255. 3.506. 2.87
Hydroxylamine, NH2OH, is a weak base. The following is the equilibrium equation for its reaction with water:NH2OH(aq) + H2O(l) ⇌ NH3OH+(aq) + OH -       Kb = 9.1 x 10 -9What is the pOH of a 2.37 M NH 2OH solution?a) 1.15b) 3.83c) 4.99d) 6.72e) 8.13
If the Kb of a weak base is 6.0 x 10-6, what is the pH of a 0.44 M solution of this base?
A certain weak base has a Kb of 8. 40 x 10-7, What concentration of this base will produce a pH of 10.21? 
Calculate the pH and concentrations of CH3NH2 and CH3NH3+ in a 0.0343 M methylamine (CH3NH2) solution. The Kb of CH3NH2 = 4.47 x 10-4. pH= [CH3NH2] = [CH3NH3+] = 
If the Kb of a weak base is 6.8 x 10-6, what is the pH of a 0.20 M solution of this base? pH = 
A certain weak base has a Kb of 8.40 x 10 -r. concentration of this base will produce a pH of 10.05?
Morphine is an effective pain killer but is also highly addictive. Calculate the pH of a 0.105 M solution of morphine if its pKb = 5.79.
Determine the pH of each of the following solutions. 0.16 M NaC2H3O2. Express your answer to two decimal places.
The base protonation constant Kb of ammonia (NH3) is 1.8 x 10 -5. Calculate the pH of a 0.95 M solution of ammonia at 25 °C. Round your answer to 1 decimal place.
What is the pH of a 0.94 M solution of the weak base pyridine (C  5H5N Kb = 1.7 x 10 -9)?
If the Kb of a weak base is 35 x 10 -6, what is the pH of a 0.26 M solution of this base?
If the Kb of a weak base is 1.7 x 10 -6, what is the pH of a 0.25 M solution of this base?
A student makes a 0.444 M solution of a weak base (B:) that has a pH of 8.94. Determine the Kb, for this base. 
Part ACalculate the molar concentration of OH- ions in a 7.6 x 10-2 M solution of ethylamine (C2H5NH2) (Kb = 6.4 x 10-4). Express your answer using two significant figures. Part B Calculate the pH of this solution. Express your answer using two decimal places.
Calculate the pH of 0.024 M ammonia. NH3 (aq) + H2O (l) <->  OH - (aq) + NH4+(aq)     K b = 1.75 x 10 -5 
The base protonation constant Kb of ammonia (NH3) is 1.8 x 10-5. Calculate the pH of a 0.77 M solution of ammonia at 25°C. Round your answer to 1 decimal place.
A certain weak base has a Kb of 7. 10 x 10. What concentration of this base will produce a pH of 10.30?
If the Kb of a weak base is 5.4 x 10-6, what is the pH of a 0.50 M solution of this base?
A certain weak base has a Kb of 8.60 x 10-7. What concentration of this base will produce a pH of 10.14?
Calculate the pH of a solution prepared by mixing 0.000125 moles of HCOO- (Ka = 1.7 x 10-4) in 150.0 mL of water.
A solution of 0.4270 M base B(aq) was prepared and the pH measured as 11.14. Calculate the pKb for the base. Enter the pKb with 2 decimal places.
Ammonia, HN3, has a Kb = 1.8 x 10 -5. What is the pH of solution that of ammonia with a concentration of 0.450 M? 
Using data from Appendix D in the textbook, calculate [OH-] and pH for each of the following solutions. Part A 7.0 x 10-2 M NaCN. Express your answer using two significant figures. [OH-] = _________ M Part BExpress your answer using two decimal places. pH =_______
Calculate the concentrations of all species in a 0.700 M NaCH3COO (sodium acetate) solution. The ionization constant for acetic acid is K, = 1.8 x 10-5.[Na+] =                                                   [CH3COO-] = [OH-] =                                                   [CH3COOH] =[H3O+] = 
What is the pH of a 0.470 M solution of methylamine (CH2NH2. Kb = 4.4 x 10-4)?
Ammonia, NH3, is a weak base with a Kb value of 1.8 x 10 -5. What is the pH of a 0.390 M ammonia solution? What is the percent ionization of ammonia at this concentration?
A 25.0-mL sample of 0.125 M pyridine is titrated with 0.100 MHCl. Calculate the pH at 0 mL of added acid. Express your answer using two decimal places.