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

Solution: 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

Solution: 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

Problem

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. 1.96

2. 2.93

3. 2.57

4. 0.25

5. 3.50

6. 2.87

Solution

We are being asked to calculate the pKb for a 0.1 M solution of C4H9NH2 (butylamine). 

C4H9NH2 (butylamine) is a neutral amine, therefore we know that it is a weak base.


We can calculate the pKb of butylamine from its Kb using the following equation:

pKb=-log Kb


Since we’re dealing with a weak base and Kb is an equilibrium expression we will have to create an ICE chart to determine the equilibrium concentration of each species:

C4H9NH2weak baseproton acceptor
H2O → will act as the weak acidproton donor


Equilibrium reaction:        C4H9NH2(aq) + H2O(l)  C4H9NH3+(aq) + OH-(aq)

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