Ch.16 - Aqueous Equilibrium WorksheetSee 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
Sections
Buffer
Acid and Base Titration Curves
Weak Acid Strong Base Titrations
Weak Base Strong Acid Titrations
Strong Acid Strong Base Titrations
Titrations of Diprotic and Polyprotic Acids
Ksp
Additional Practice
Equivalence Point
Acid Base Indicators
Selective Precipitation
Formation Constant
Additional Guides
Henderson Hasselbalch Equation (IGNORE)
LearnAdditional Practice
Next SectionStrong Acid Strong Base Titrations

Whenever a WEAK BASE reacts with a STRONG ACID we use an ICF Chart to determine the pH of the solution. 

Weak Base Strong Acid Titrations

Concept #1: Understanding Weak Acid–Strong Base titration reactions

Concept #2: If you use an ICF Chart and at the end you have remaining weak acid and conjugate base then you have a buffer so you use the Henderson-Hasselbalch Equation to find pH. 

Concept #3: If any excess moles of the strong acid remain then we will use its concentration to find the pH of the solution. 

Concept #4: If the moles of both the conjugate base and strong acid are equal then we will have only weak acid at the end of our ICF Chart Calculation. To find pH we would follow up with an ICE Chart. 

Weak Base Strong Acid Titration Calculations

Example #1:

A buffer contains 167.2 mL of 0.25 M propanoic acid, CH3CH2COOH, with 138.7 mL of 0.42 M sodium propanoate, CH3CH2COONa. Find the pH after the addition of 150.2 mL of 0.56 M HCl. The Ka of CH3CH2COOH is 1.3 x 10-5.

 

Example #2: Calculate the pH of the solution that results from the mixing of 75.0 mL of 0.100 M NaC2H3O2 and 75.0 mL of 0.150 M HC2H3O2 with 0.0025 moles of HBr. Ka of HC2H3O2 is 1.8 x 10-5.    

Previous SectionWeak Acid Strong Base Titrations
Next SectionStrong Acid Strong Base Titrations
Additional Problems
Which of the following is the best choice to titrate 0.10 M C  6H5NH2? a) 0.30 M NaOH b) 0.01 M NH 3 c) 0.10 M HNO3 d) 0.10 M HCO2H
Consider the titration of 100.0 mL of 0.250 M aniline (Kb = 3.8 x 10  -10) with 0.500 M HCl. What is the pH of the solution at the stoichiometric point? A. -0.85 B. 8.70 C. 2.68 D. 11.62 E. none of these 
A 250.0-mL solution buffer solution is 0.250 M in acetic acid and 0.250 M in sodium acetate. The acid dissociation constant of acetic acid is 1.8 x 10-5.  i. What is the initial pH of this solution?         ii. What is the pH after addition of 0.0050 mol of HCl?               iii. What is the pH after addition of 0.0050 mol of NaOH?
A 75.0-mL volume of 0.200 M NH 3 (Kb = 1.8 x 10-5) is titrated with 0.500 M HNO3. Calculate the pH after the addition of 13.0-mL of HNO3.
What is the pH of a 0.20 M NH 3/0.20 M NH4Cl buffer after 15 mL of 0.15 M HCl has been added to 65 mL of buffer?
You add a small amount of HCl to a solution of 0.20 M HBrO and 0.20 M NaBrO. What do you expect to happen? 1. The [OH−] will decrease slightly. 2. The H+ ions will react with the HBrO molecules. 3. The pH will increase slightly. 4. The Ka for HBrO will increase. 
A buffer contains 55.3 mL of 0.200 M nitrous acid, HNO 2, with 100.0 mL of 0.550 M sodium nitrite, NaNO2. Find the pH after the addition of 180.0 mL of 0.400 M HClO  4. The Ka of HNO2 is 4.6 x 10-4. 
What is the pH at the equivalence point of a weak base-strong acid titration if 20.00 mL of NaOCl requires 28.30 mL of 0.50 M HCl to reach the equivalence point? The acid dissociation constant of HOCl is 3.0x10-8.3.760.303.184.03
What is the pH of a 0.20 M NH 3/0.20 M NH4Cl buffer after 10 mL of 0.10 M HCl has been added to 65 mL of buffer?
A student creates 150.00mL of a buffer that is 0.018 M in formic acid and 0.016 M in sodium formate. What would the pH of the buffer be after the addition of 15.00 mL of a 0.070 M HCl solution to the buffer?A. 3.69B. 3.85C. 4.18D. 1.15E. 3.30
In order to create a buffer 7.321 g of potassium lactate is mix with 550.0 mL of 0.328 M lactic acid, HC3H5O3. What is the pH of the buffer solution after the addition of 700.0 mL of 0.100 M hydrobromic acid, HBr? The Ka of HC3H5O3 is 1.4 x 10-4.
How does a buffer resist change in pH upon addition of a strong acid?a) The strong acid reacts with the weak base in the buffer to form a weak acid, which produces few H+ ions in solution and therefore only a little change in pH.b) The strong acid reacts with the weak acid in the buffer to form a weak base, which produces few H+ ions in solution and therefore only a little change in pH.c) The strong acid reacts with the strong base in the buffer to form a salt which, produces few H  + ions in solution and therefore only a little change in pH.
Which of the following occurs when HCl is added to a buffer containing (CH3)3N and (CH3)3NH+?  a. The concentration of (CH3)3N will increase.b. The concentration of (CH3)3NH+ will increase.c. The concentration of (CH3)3N will decrease.d. The concentration of (CH3)3NH+ will decrease.
A 25.0-mL sample of 0.125 M pyridine is titrated with 0.100 MHCl. Calculate the pH at equivalence point. Express your answer using two decimal places.
A 25.0-mL sample of 0.125 M pyridine is titrated with 0.100M HCl. Calculate the pH at 50 mL of added acid. Express your answer using two decimal places.
20 mL of 0.25 M of NH 3 is titrated with 0.40 M HCl. Calculate the pH of the solution after 20 mL HCl is added. Kb (NH3) = 1.8 × 10 −5.a. 12.50b. 7.00c. 4.74d. 1.12
A 1.00 L buffer solution is 0.250 M in HF and 0.250 M in NaF. Calculate the pH of the solution after the addition of 100.0 mL of 1.00 M HCl. The Ka for HF is 3.5 × 10-4. A) 3.09B) 4.11C) 3.82D) 3.46E) 2.78
Calculate the pH during the titration of 20.00 mL of 0.1000 M ammonia with 0.1000 M HCl(aq) after 15 mL of the acid have been added. Kb of ammonia = 1.8 x 10-5.
A 1.00 L buffer solution is 0.150 M in HC 7H5O2 and 0.250 M in LiC7H5O2. Calculate the pH of the solution after the addition of 100.0 mL of 1.00 M HCl. The Ka for HC7H5O2 is 6.5 x 10-5.