Concept explainers
Aqueous Solutions of Acids, Bases, and Salts
- a For each of the following salts, write the reaction that occurs when it dissociates in water: NaCl(s), NaCN(s), KClO2(s), NH4NO3(s), KBr(aq), and NaF(s).
- b Consider each of the reactions that you wrote above, and identify the aqueous ions that could be proton donors (acids) or proton acceptors (bases). Briefly explain how you decided which ions to choose.
- c For each of the acids and bases that you identified in pan b, write the chemical reaction it can undergo in aqueous solution (its reaction with water).
- d Are there any reactions that you have written above that you anticipate will occur to such an extent that the pH of the solution will be affected? As pan of your answer, be sure to explain how you decided.
- e Assume that in each case above, 0.01 mol of the salt was dissolved in enough water at 25°C to make 1.0 L of solution. In each case what additional information would you need in order to calculate the pH? If there are cases where no additional information is required, be sure to state that as well.
- f Say you take 0.01 mol of NH4CN and dissolve it in enough water at 25°C to make 1.0 L of solution. Using
chemical reactions and words, explain how you would go about determining what effect this salt will have on the pH of the solution. Be sure to list any additional information you would need to arrive at an answer.
(a)
Interpretation:
The reaction of the given salts when it dissociates in water has to be written.
Concept Introduction:
Salt hydrolysis:
Salt hydrolysis is a reaction in which the ion of salt reacts with water and produce either hydronium ion or hydroxide ion.
Based on pH of the solution, salt solutions can be classified as
- Acidic-(pH will be less than seven)
- Basic -(pH will be more than seven)
- Neutral -(pH will be equal to seven)
To Write: The reaction of the given salts when it dissociates in water
Answer to Problem 16.21QP
The reaction of salt
The reaction of salt
The reaction of salt
The reaction of salt
The reaction of salt
The reaction of salt
Explanation of Solution
The reaction of the salt
The reaction of the salt
The reaction of the salt
The reaction of the salt
The reaction of the salt
The reaction of the salt
The reaction of salt
The reaction of salt
The reaction of salt
The reaction of salt
The reaction of salt
The reaction of salt
(b)
Interpretation:
From the reactions given in part (a), the aqueous ions which are proton donors (acids) and proton acceptors (bases) has to be identified.
Concept Introduction:
Salt hydrolysis:
Salt hydrolysis is a reaction in which the ion of salt reacts with water and produce either hydronium ion or hydroxide ion.
Based on pH of the solution, salt solutions can be classified as
- Acidic-(pH will be less than seven)
- Basic -(pH will be more than seven)
- Neutral -(pH will be equal to seven)
To Identify: The proton donors (acids) and proton acceptors (bases) from part (a)
Answer to Problem 16.21QP
The ion which is a proton donor (acid) is
The ions which are a proton acceptors (bases) are
Explanation of Solution
Ions as Proton donors:
The ion to be a proton donor must possess hydrogen and must be cation.
Thus, the only cation ion which possess hydrogen is
Hence, the ion which acts as proton donor (acid) is
Ions as Proton acceptors:
The proton acceptor must be an anion and are conjugate bases of weak acids.
The possible proton acceptors from the reactions in part (a) are
The ion which is a proton donor (acid) is identified as
The ions which are a proton acceptors (bases) are identified as
(c)
Interpretation:
The chemical reaction in water for each of the acids and bases identified in part (b) has to be written.
Concept Introduction:
Salt hydrolysis:
Salt hydrolysis is a reaction in which the ion of salt reacts with water and produce either hydronium ion or hydroxide ion.
Based on pH of the solution, salt solutions can be classified as
- Acidic-(pH will be less than seven)
- Basic -(pH will be more than seven)
- Neutral -(pH will be equal to seven)
To Write: The chemical reaction in water for each of the acids and bases identified in part (b)
Answer to Problem 16.21QP
The chemical reaction in water for each of the acids and bases identified in part (b) are:
Explanation of Solution
Chemical reaction in water for the acids and bases:
The ion
The ion
The ion
The ion
The chemical reaction in water for each of the acids and bases identified in part (b) are:
(d)
Interpretation:
Does any of the reactions written in part (c) will occur to such an extent that the pH of the solution will be affected has to be explained
Concept Introduction:
Relationship between
Where
Autoionization of water is the reaction in which the water undergoes ionization to give a proton and a hydroxide ion. The ionization of water is an equilibrium reaction and hence this has equilibrium rate constant.
To Explain: Does any of the reactions written in part (c) will occur to such an extent that the pH of the solution will be affected
Explanation of Solution
On seeing at the
We know that,
Every acid will have a conjugate base.
For the acids with smaller
Does any of the reactions written in part (c) will occur to such an extent that the pH of the solution will be affected was explained.
(e)
Interpretation:
On assuming that
Concept Introduction:
Salt hydrolysis:
Salt hydrolysis is a reaction in which the ion of salt reacts with water and produce either hydronium ion or hydroxide ion.
Based on pH of the solution, salt solutions can be classified as
- Acidic-(pH will be less than seven)
- Basic -(pH will be more than seven)
- Neutral -(pH will be equal to seven)
Explanation of Solution
For the solutions made from either
The
For the solutions made from
The additional informations that are either needed or not needed in order to calculate the pH for each of the given solutions was explained
(f)
Interpretation:
The effect of salt
Concept Introduction:
Relationship between
Where
Autoionization of water is the reaction in which the water undergoes ionization to give a proton and a hydroxide ion. The ionization of water is an equilibrium reaction and hence this has equilibrium rate constant.
To Explain: The effect of salt
Explanation of Solution
Given data:
A 0.01 mol of
Effect of salt on pH calculation:
From the given data, we know the concentration of the solution would be
The soluble
Both the ions undergoes hydrolysis as follows,
Since
Therefore, the
Both of these reactions involve a conjugate acid or base, so it is necessary to compare the
The smaller the
we need the
The effect of salt
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Chapter 16 Solutions
General Chemistry - Standalone book (MindTap Course List)
- What is a salt? List some anions that behave as weak bases in water. List some anions that have no basic properties in water. List some cations that behave as weak acids in water. List some cations that have no acidic properties in water. Using these lists, give some formulas for salts that have only weak base properties in water. What strategy would you use to solve for the pH of these basic salt solutions? Identify some salts that have only weak acid properties in water. What strategy would you use to solve for the pH of these acidic salt solutions? Identify some salts that have no acidic or basic properties in water (produce neutral solutions). When a salt contains both a weak acid ion and a weak base ion, how do you predict whether the solution pH is acidic, basic, or neutral?arrow_forwardIonization of the first proton from H2SO4 is complete (H2SO4 is a strong acid); the acid-ionization constant for the second proton is 1.1 102. a What would be the approximate hydronium-ion concentration in 0.100 M H2SO4 if ionization of the second proton were ignored? b The ionization of the second proton must be considered for a more exact answer, however. Calculate the hydronium-ion concentration in 0.100 M H2SO4, accounting for the ionization of both protons.arrow_forwardIonization of the first proton from H2SeO4 is complete (H2SeO4 is a strong acid); the acid-ionization constant for the second proton is 1.2 102. a What would be the approximate hydronium-ion concentration in 0.150 M H2SeO4 if ionization of the second proton were ignored? b The ionization of the second proton must be considered for a more exact answer, however. Calculate the hydronium-ion concentration in 0.150 M H2SeO4, accounting for the ionization of both protons.arrow_forward
- Methyl orange, HMO, is a common acid-base indicator. In solution it ionizes according to the equation: HMOaqH+aq+MO-aqredyellow If methyl orange is added to distilled water, the solution turns yellow. If 1 drop or two of 6 M HCl is added to the yellow solution, it turns red. If to that solution one adds a few drops of 6 M NaOH, the color reverts to yellow. a. Why does adding 6 M HCl to the yellow solution of methyl orange tend to cause the color to change to red? Note that in solution HCl exists as H+ and Cl- ions. b. Why does adding 6 M NaOH to the red solution tend to make it turn back to yellow? Note that in solution NaOH exists as Na+ and OH- ions. How does increasing OH- shift Reaction 3 in the discussion section? How would the resulting change in H+ affect the dissociation reaction of HMO?arrow_forwardConsider all acid-base indicators discussed in this chapter. Which of these indicators would be suitable for the titration of each of these? (a) NaOH with HClO4 (b) acetic acid with KOH (c) NH3 solution with HBr (d) KOH with HNO3 Explain your choices.arrow_forwardStrong Acids, Weak Acids, and pH Two 0.10-mol samples of the hypothetical monoprotic acids HA(aq) and HB(aq) are used to prepare 1.0-L stock solutions of each acid. a Write the chemical reactions for these acids in water. What are the concentrations of the two acid solutions? b One of these acids is a strong acid, and one is weak. What could you measure that would tell you which acid was strong and which was weak? c Say that the HA(aq) solution has a pH of 3.7. Is this the stronger of the two acids? How did you arrive at your answer? d What is the concentration of A(aq) in the HA solution described in part c? e If HB(aq) is a strong acid, what is the hydronium-ion concentration? f In the solution of HB(aq), which of the following would you expect to be in the greatest concentration: H3O+(aq), B(aq), HB(aq), or OH(aq)? How did you decide? g In the solution of HA(aq), which of the following would you expect to be in the greatest concentration: H3O+(aq), A+(aq), HA(aq), or OH(aq)? How did you decide? h Say you add 1.0 L of pure water to a solution of HB. Would this water addition make the solution more acidic, make it less acidic, or not change the acidity of the original solution? Be sure to fully justify your answer. i You prepare a 1.0-L solution of HA. You then take a 200-mL sample of this solution and place it into a separate container. Would this 200 mL sample be more acidic, be less acidic, or have the same acidity as the original 1.0-L solution of HA(aq)? Be sure to support your answer.arrow_forward
- . The concepts of acid-base equilibria were developed in this chapter for aqueous solutions (in aqueous solutions, water is the solvent and is intimately involved in the equilibria). However, the Brønsted-Lowry acid-base theory can be extended easily to other solvents. One such solvent that has been investigated in depth is liquid ammonia. NH3. a. Write a chemical equation indicating how HCl behaves as an acid in liquid ammonia. b. Write a chemical equation indicating how OH- behaves as a base in liquid ammonia.arrow_forwardWrite the chemical equation and the expression for the equilibrium constant, and calculate Kb for the reaction of each of the following ions as a base. (a) sulfate ion (b) citrate ionarrow_forwardThe preparations of two aqueous solutions are described in the table below. For each solution, write the chemical formulas of the major species present at equilibrium. You can leave out water itself. Write the chemical formulas of the species that will act as acids in the 'acids' row, the formulas of the species that will act as bases in the 'bases' row, and the formulas of the species that will act as neither acids nor bases in the 'other' row. You will find it useful to keep in mind that HF is a weak acid. 0.5 mol of NaOH is added to 1.0L of a 0.5M HF solution. acids: bases: other: 0.076 mol of HI is added to 1.0L of a solution that is 1.3M in both HF and KF. acids: bases: other:arrow_forward
- Write an equation in which HSO3- acts as an acid. (Use the lowest possible coefficients. Be sure to to specify states such as (aq) or (s). If a box is not needed, leave it blank.) HSO3-(aq) + OH-(aq) ----- + Write an equation in which HSO3- acts as an base. (Use the lowest possible coefficients. Be sure to to specify states such as (aq) or (s). If a box is not needed, leave it blank.) HSO3-(aq) + H3O+(aq) ----- +arrow_forwardEach of the four flasks below contains the same volume of .10 M aqueous acid. All four acids are monoprotic, meaning that each acid molecule gives up one H+. The pH of each solution is as indicated. Flask A: pH=1.1 Flask B: pH=2.4 Flask C pH= 2.9 Flask D: pH=5.1 How much strong base is required to neutralize the initial amount of acid? A. All four solutions will require the same amount of base because they all contain acid of the same concentration B. The solution of pH=1.1 will require the most base since it is the strongest acid and has the highest concentration of H+ C. Neither (A) nor (B) is correct.arrow_forwardWhat is the pOH of a solution prepared by diluting 50ml of 0.06M HCl with 20ml of distilled water? What is the pH of a solution containing 5ml of 0.1M NaOH mixed with 2ml of 0.15M HCl? Which of the following aqueous solutions will have the highest conductivity? The same experiment was conducted for methanol. What would be the intensity of the light bulb? Which of the following aqueous solutions will exhibit no conductivity at all?arrow_forward
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