
Concept explainers
Interpretation:
The pH of the solutions prepared by the dissolution of the given weak bases are to be determined at
Concept introduction:
The ionization of the weak base takes place as
The formula to calculate the pOH of the solution from the concentration of hydroxide ions is
Kb is the measure of dissociation of a base and is known as the base-ionization constant, which is specific at a particular temperature.
Percent ionization is the percentage of base that gets dissociated upon addition to water. It depends on the hydroxide ion concentration.
Here,
pH is the measure of acidity of a solution, which depends on the concentration of hydronium ions and the temperature of the solution. The relationship between pH and pOH is

Answer to Problem 68QP
Solution:
(a)
(b)
Explanation of Solution
a)
Refer to Table
When a weak base is dissolved in water, only partial dissociation takes place into
The reaction of ammonia is depicted as
First, prepare an equilibrium table and represent each of the species in terms of
Now, substitute these concentrations in equation (2) as
Since the value of Kb is very small, the quantity of base dissociated is less. Therefore,
Thus,
Calculate the percent dissociation from equation (3) as follows:
Since the percent dissociation is less than
Now, use equation (1) to calculate the pOH of the solution:
Now, use equation (4) to calculate the pH of the solution:
Therefore, the pH of the solution is
b)
When a weak base is dissolved in water, only partial dissociation takes place into
The reaction of pyridine is depicted as follows:
First, prepare an equilibrium table and represent each of the species in terms of
Now, substitute these concentrations in equation (2):
Since the value of Kb is very small, the quantity of base dissociated is less. Therefore,
Thus,
Calculate the percent dissociation from equation (3):
Since the percent dissociation is less than
Now, use equation (1) to calculate the pOH of the solution:
Now, use equation (4) to calculate the pH of the solution:
Therefore, the pH of the solution is
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Chapter 16 Solutions
CHEMISTRY >CUSTOM<
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- Curved arrows are used to illustrate the flow of electrons. Use the reaction conditions provided and follow the curved arrows to draw the product of this elementary step in an elimination mechanism. Include all lone pairs and charges as appropriate. Ignore stereochemistry. Ignore byproducts. + Br: .. 8 0.01 M NaOH heat Drawing Q Atoms, Bonds and Rings Charges and Lone Pairs Draw or tap a new bond to see suggestions. Undo Reset Remove Done + Drag To Panarrow_forward+ Draw the product of the E2 reaction shown below. Include the correct stereochemistry. Ignore any inorganic byproducts. Ph CH2CH3 H H3C H Br DBN [૪] Drawing Atoms, Bonds and Rings H | OH Charges ―00 H. C | Undo Reset Br I Remove Done Drag To Pan +arrow_forwardReaction A Now the production A Œ In the product of reaction i 12 Dear the product of actionarrow_forward
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- + Draw an alkyl halide that produces ONLY the following alkene in an E2 elimination. Ignore any inorganic byproducts. Drawing Strong Base Q Atoms, Bonds and Rings Charges HO Br H2N Undo Reset Remove Done Drag To Panarrow_forwardFor the dehydrohalogenation (E2) reaction shown, draw the major organic product. Хок Br tert-butanol heat Select Drew Templates More Erase CH QQQarrow_forwardMacmillan Learning Draw the major, neutral organic product for each substitution reaction. For this question, assume that each substitution reaction goes to completion. Disregard elimination. Reaction A. CI H₂O Select Draw Templates More Erase C Harrow_forward
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