Concept explainers
For each of the following cases, decide whether the pH is less than 7, equal to 7, or greater than 7.
(a) Equal volumes of 0.10 M acetic acid, CH3CO2H, and 0.10 M KOH are mixed.
(b) 25 mL of 0.015 M NH3 is mixed with 12 mL of 0.015 M HCl.
(c) 150 mL of 0.20 M HNO3, is mixed with 75 mL of 0.40 M NaOH.
(d) 25 mL of 0.45 M H2SO4 is mixed with 25 mL of 0.90 M NaOH.
(a)
Interpretation:
The value of
Concept introduction:
For weak acid-strong base titration the
Explanation of Solution
The
Given:
Refer to table 16.2 in the textbook for the value of
The value of
The value of
The
Substitute,
Therefore,
The initial concentration of
The initial concentration of
The volume of
Therefore, let the volume of
Thus volume of
Therefore, total volume after reaction is
The calculation of moles is done by using the expression,
The ICE table (1) for the reaction between
From ICE table (1),
Calculate the concentration of acetate ion after reaction.
Substitute,
The concentration of acetate ion after reaction is
The acetate ion produced will undergo hydrolysis in presence of water and the reaction equilibrium is written as,
The hydrolysis equilibrium is represented in ICE table (2).
From ICE table (2),
There is an approximation, that the value of
Therefore, Concentration of acetate ion left after reaction is
Calculate the concentration of
Rearrange it for
The expression of
Equate equation (5) and (6),
Substitute,
Rearrange for
Rearrange for
The value of
Calculate the value of
Substitute,
Therefore, the value of
Thus, the value of
Rearrange for
Substitute,
Therefore, the value of
The value of
(b)
Interpretation:
The value of
Concept introduction:
For weak base-strong acid titration the
The equilibrium established during the titration of
Explanation of Solution
The
As the addition of
The
Given:
Refer to table 16.2 in the textbook for the value of
The value of
The
Substitute,
Therefore,
The initial concentration of
The initial concentration of
The volume of
The volume of
The total volume after the reaction is calculated as,
Therefore, total volume after reaction is
The calculation of moles is done by using the expression,
The ICE table (2) for the reaction between
From ICE table (2),
Number of moles of ammonia left after reaction are
Number of moles of
Number of moles of ammonium ion
Concentration calculations is done by using the expression,
Therefore, concentration of ammonium ion
Concentration of ammonia after reaction is
Calculate the
Substitute,
Therefore, the value of
Thus
Substitute,
Rearrange for
Therefore, the value of
The value of
(c)
Interpretation:
The value of
Concept introduction:
Strong acid-Strong base, in this type of titration a strong acid is titrated against a strong base for example,
Explanation of Solution
The
Given:
The initial concentration of
The volume of
The initial concentration of
The volume of
The table gives the moles of reactant and product for the reaction between
After the reaction there is no moles of acid and base are present in the reaction mixture. That means all acid and base has been neutralized and titration has reached the equivalence point.
For the strong acid and strong base titration the
The value of
(d)
Interpretation:
The value of
Concept introduction:
Strong acid-Strong base, in this type of titration a strong acid is titrated against a strong base for example,
The sulphuric acid is a dibasic acid as it has two hydrogen atoms which can be donated.
Therefore two equivalents of
Explanation of Solution
The
Given:
The initial concentration of
The volume of
The initial concentration of
The volume of
The table gives the moles of reactant and product for the reaction between
After the reaction there is no moles of acid and base are present in the reaction mixture. That means all acid and base has been neutralized and titration has reached the equivalence point.
For the strong acid and strong base titration the
The value of
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Chapter 17 Solutions
Chemistry & Chemical Reactivity
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- Chemistry: Principles and PracticeChemistryISBN:9780534420123Author:Daniel L. Reger, Scott R. Goode, David W. Ball, Edward MercerPublisher:Cengage Learning