Concept explainers
You titrate 25.0 mL of 0.10 M NH3 with 0.10 M HCl.
- (a) What is the pH of the NH3 solution before the titration begins?
- (b) What is the pH at the equivalence point?
- (c) What is the pH at the halfway point of the titration?
- (d) What indicator in Figure 17.11 could be used to detect the equivalence point?
- (e) Calculate the pH of the solution after adding 5.00, 15.0, 20.0, 22.0, and 30.0 mL of the acid. Combine this information with that in parts (a)–(c) and plot the titration curve.
(a)
Interpretation:
The value of
Concept introduction:
Titration is a quantitative method to determine the quantity of an acid or base in a solution. This method is used to determine the concentration an acid in the solution by titrating it against a base.
For strong acid-weak base titration, the
Calculation of
(1) The
(2) The
As the addition of
At the midpoint of the titration, the concentration of acid and its conjugate base is equal. Therefore
Substitute,
Therefore,
(3) The
At equivalence point, all the base will be neutralized, and there will be only
By using the value of
The relation between
Explanation of Solution
The
Given:
Refer to the Appendix I in the textbook for the value of
The value of
The initial concentration of
The initial concentration of
The volume of the solvent is
Therefore the volume of the solvent is
ICE table (1) gives the ionization reaction of
From the ICE table (1),
The concentration of
The concentration of ammonium ion produced after the reaction is
The concentration of
There is an approximation, that the value of
Therefore, Concentration of
The hydroxide ion concentration is calculated by the expression,
Substitute
Rearrange for
Therefore, the concentration of hydroxide ion is
Calculate the
Substitute
The relation between
Substitute the value of
The value of
(b)
Interpretation:
The value of
Concept introduction:
Titration is a quantitative method to determine the quantity of an acid or base in a solution. This method is used to determine the concentration an acid in the solution by titrating it against a base.
For strong acid-weak base titration, the
Calculation of
(1) The
(2) The
As the addition of
At the midpoint of the titration, the concentration of acid and its conjugate base is equal. Therefore
Substitute,
Therefore,
(3) The
At equivalence point, all the base will be neutralized, and there will be only
By using the value of
The relation between
Explanation of Solution
The value of
Given:
The volume of
An expression used for the neutralization is as follows,
Here,
Substitute
Rearrange for
Therefore, the volume of the
The calculation of moles is done by using the expression,
The ICE table (2) for the reaction between
From the ICE table (2),
A number of moles of ammonia left after reaction is
A number of moles of ammonium ion produced after the reaction is
The total volume after the reaction is calculated as,
Therefore, total volume after the reaction is
Concentration calculations are done by using the expression,
Calculate the concentration of ammonium ion after the reaction.
Substitute,
The concentration of Ammonium ion after the reaction is
The ammonium ion produced will undergo hydrolysis in presence of water and the reaction equilibrium is written as,
The hydrolysis equilibrium is represented in ICE table (3).
From the ICE table (3),
The concentration of ammonium ion left after the reaction is
The approximation
So, Concentration of ammonium ion left after the reaction is
The concentration of ammonia produced after the reaction is
The concentration of
Calculate the concentration of
Rearrange it for
Substitute
Therefore,
The expression of
Substitute,
Rearrange for
Therefore the value of
Calculate the value of
Substitute,
Therefore, the value of
(c)
Interpretation:
The value of
Concept introduction:
Titration is a quantitative method to determine the quantity of an acid or base in a solution. This method is used to determine the concentration an acid in the solution by titrating it against a base.
For strong acid-weak base titration, the
Calculation of
(1) The
(2) The
As the addition of
At the midpoint of the titration, the concentration of acid and its conjugate base is equal. Therefore
Substitute,
Therefore,
(3) The
At equivalence point, all the base will be neutralized, and there will be only
By using the value of
The relation between
Explanation of Solution
The
Given:
The value of
The value of
The
The relation between
Rearrange it for
Substitute
Therefore,
Substitute,
Therefore,
At the midpoint of the titration, the concentration of acid and its conjugate base will be equal.
Substitute
Therefore, the value of
(d)
Interpretation:
The value of
Concept introduction:
Titration is a quantitative method to determine the quantity of an acid or base in a solution. This method is used to determine the concentration an acid in the solution by titrating it against a base.
For strong acid-weak base titration, the
Calculation of
(1) The
(2) The
As the addition of
At the midpoint of the titration, the concentration of acid and its conjugate base is equal. Therefore
Substitute,
Therefore,
(3) The
At equivalence point, all the base will be neutralized, and there will be only
By using the value of
The relation between
Explanation of Solution
Methyl red and bromcresol green are the best indicators for the titration between ammonia and hydrochloric acid. As it changes its color in the
(e)
Interpretation:
The value of
Concept introduction:
Titration is a quantitative method to determine the quantity of an acid or base in a solution. This method is used to determine the concentration an acid in the solution by titrating it against a base.
For strong acid-weak base titration, the
Calculation of
(1) The
(2) The
As the addition of
At the midpoint of the titration, the concentration of acid and its conjugate base is equal. Therefore
Substitute,
Therefore,
(3) The
At equivalence point, all the base will be neutralized, and there will be only
By using the value of
The relation between
The value of
Graph between
Explanation of Solution
At various points, before the equivalence point, the value of
Given:
When
After titration volume will be equal for both acid and base. The total volume will be
The calculation is done by using equation (1),
Substitute
Therefore the value of
When
After titration volume will be equal for both acid and base. The total volume will be
The calculation is done by using equation (1),
Substitute
Therefore the value of
When
After titration volume will be equal for both acid and base. The total volume will be
The calculation is done by using equation (1),
Substitute
Therefore the value of
When
After titration volume will be equal for both acid and base. The total volume will be
The calculation is done by using equation (1),
Substitute
Therefore the value of
When
After titration volume will be equal for both acid and base. The total volume will be
After the equivalence point, the excess concentration of
The concentration of hydrogen ion after the equivalence point is calculated.
Therefore, the concentration of hydrogen ions after the reaction is
Calculate the
Therefore the value of
The titration curve is drawn by using the
The table gives the value of
Graph between
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Chapter 17 Solutions
Chemistry and Chem. React., Hybrid Edition
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