SB Acid-Base II

A 0.10 M CH3COOH solution has a [H3O+] = 1.3 x 10-3 M. What is the percent ionization of CH3COOH with a Ka = 1.8 x 10-5?

1.3%

What is the pH of a 0.25 M solution of ethanolamine (Kb = 3.2 x 10-5)?

11.45

Nitrous acid, HNO2, has a Ka of 7.1 x 10-4. What is the [H3O+] in a 0.60 M solution of HNO2?

2.1 x 10-2 M

Benzoic acid, C6H5CO2H, has a Ka of 6.5 x 10-5. What is the pH of a 0.40 M solution of benzoic acid?

2.29

Calculate the kaka value for the anilium ion (C6H5NH3+C6H5NH3+) if kbkb for aniline (C6H5NH2C6H5NH2) is 4.0 × 10−1010-10

2.5 × 10-5

Match each acid correctly to the number of ionizable protons. -H3PO4 -H2CO3 -CH3CHOOH

3 2 1

Match each acid with its correct Ka at 25oC given that HCN is the weakest and HF is the strongest of the acids listed. -HCN -CH3COOH -HF

4.9 1.8 7.1

When calculating the pH of a weak acid solution it is justified to assume that [H3O+] derived from the acid is negligible when the [H3O+] is less than _____ % of the initial acid concentration.

5

A 0.10 M solution of HCN (Ka = 4.9 x 10-10) is 7.0 x 10-3 % ionized. What is the pH of this solution?

5.15

Calculate the kbkb value for the acetate ion (CH3COO−CH3COO-) if the kaka value for acetic acid (CH3COOHCH3COOH) is 1.8 × 10−510-5.

5.6 × 10-10

The pH of a salt solution containing a small, highly charged metal cation is influenced by the hydrolysis reaction of the metal ion. Which of the following statements correctly explain the hydrolysis reaction of these metal cations? Select all that apply.

A hydrated metal ion produces an acidic solution because the metal ion withdraws electron density from the O-H bond, facilitating loss of H+. Small, highly charged metal cations accept electron pairs from water molecules and form hydrated ions.

Which of the following statements correctly describe amphoteric hydroxides? Select all that apply.

Al(OH)3 is an amphoteric hydroxide. Amphoteric hydroxides react with both acids and bases.

Which of the following anions will produce a neutral solution in water? Select all that apply, and assume that any associated cations do not affect the pH.

I- Cl- NO3-

Which is the correct equation for the calculation of percent ionization of the weak acid HA in aqueous solution?

[H+]eq / [HA]0

A Lewis acid is any species that _____ an electron pair, whereas a Lewis base is a species that _____ an electron pair.

accepts; donates

A salt consisting of a small, highly charged metal cation and the anion of a strong acid yields a(n) _____ solution.

acidic

A salt in which the cation is the conjugate acid of a weak base will produce an ______ solution. (Assume that the anion does not hydrolyze.)

acidic

In general, nonmetal oxides tend to be _____ while metal oxides tend to be _____.

acidic, basic

A salt consisting of the _____ of a strong acid and the _____ of a strong base yields a neutral solution.

anion; cation

The strength of a weak base is indicated by its ______ -ionization constant Kb. The greater the value of Kb, the _____ the base

base stronger

An amphoteric metal hydroxide behaves not only as a(n) _______ (as expected given its OH- anion), but also as a(n) _____.

base acid

A salt in which the anion is the conjugate _____ of a weak _____ will produce a basic solution. (Assume that the cation does not hydrolyze.)

base, acid

Order the steps for calculating the kaka of a weak acid, given a solution of known concentration and pH.

calculate [H3O+] calculate substitue solve

Order the following steps in determining the pH of a solution of a weak acid of known concentration.

construct use express enter calculate

True or false: For any acid-base reaction,

false

A polyprotic acid undergoes successive ionizations, although the _____ ionization typically has a much larger ionization constant the rest.

first

The stronger the acid, the _____ the [H3O+] at equilibrium and the _____ the value of Ka.

higher; larger

As the initial concentration of a weak acid decreases, the percent ionization of the acid ______.

increases

Place the steps required to calculate the pH of a 0.10 M NaNO2 solution in the correct order.

kb 2.22 OH- pOH pH

For solutions with the same initial concentration of acid HA, the smaller the value of Ka, the ______ the % ionization and thus the ______ the acid.

lower, weaker

The degree of ionization for a weak monoprotic acid HA is given by the expression

percent

Rank the sequence of the steps you would use to calculate Kb starting with the pH of a solution of a weak base of known initial concentration.

use pH calculate use OH- use the

A strong acid ionizes completely in water; therefore it has a ______ conjugate base. A weak base reacts only partially with water; therefore it has a ______ conjugate acid.

weak; strong

In general, the stronger an acid is, the _____ its conjugate base will be. The stronger the acid, the more the equilibrium shown below will favor the formation of the _____.

weaker, conjugate base

Which of the following solutions of HCN will have the greatest percent ionization?

0.00010 M

Arrange the following acids in order of greatest (at the top of the list) to least (at the bottom of the list) amount of H3O+ produced in solution at a given concentration.

1.1 6.8 2.9 6.2

Which of the following are not steps in a process to determine the pH of a solution of a weak acid whose concentration is known? Select all that apply.

Assume that the acid is fully ionized in aqueous solution. Include the concentration of water in the equilibrium expression.

You are given a weak acid solution of known concentration and known pH. Which of the following would not be part of the process of determining the

Assume that the equilibrium [HA] is equal to the initial [HA]. Convert [H3O+][H3O+] to [OH−][OH-] for the salt solution.

Which of the following oxides will NOT produce a basic solution in water?

Cl2O

The Ka values for CH3COOH and ClCH2COOH are 1.8 x 10-5 and 5.6 x 10-2, respectively, at 25oC. Select the correct statement about the relative strengths of these acids.

ClCH2COOH is stronger than CH3COOH.

Finding the pH of a weak base solution is very similar to that for a weak acid. What is the only step that is necessary in the calculation of pH of a weak base and not a weak acid?

Convert [OH-] to [H3O+].

Select all the acids below that are diprotic and polyprotic.

H2SO4 H2C6H6O6

Which of the following statements accurately describe the characteristics of polyprotic acids? Select all that apply.

In calculations involving polyprotic acids we generally only take into account H3O+ formed from the first ionization. A polyprotic acid has more than one ionizable proton. Polyprotic acids are generally weak acids.

Select all the expressions that correctly express the relationship between

Ka = Kw / Kb Ka × Kb = Kw

Select all the statements that correctly describe the constant Ka.

Ka is the acid ionization constant. [H2O] is not included in the Ka expression for a given acid.

Which of the following correctly represents Kb for a weak base of general formula B?

Kb = [HB+][OH-] / [B]

Select all the options that correctly account for the behavior of NH4Cl in aqueous solution.

NH4+ + H2O ⇌ NH3 + H3O+ The solution will have a pH < 7.00.

Which of the following salt solutions will be basic, assuming that all have concentrations of 0.1 M? Select all that apply.

NaCN KCH3COO

Which of the following nonmetal oxides produce a weak acid when dissolved in water? Select all that apply.

P4O10 CO2

Select all the statements that correctly describe the acid-base behavior of oxides.

Some metals from Group 3A form amphoteric oxides. Alkali metal oxides are basic. Most nonmetal oxides are acidic.

An aqueous NaCl solution was found to have a pH = 7.00. Select all the statements that correctly describe this solution.

The NaCl solution was neutral. Neither Na+ nor Cl- reacts with water.

Which of the following statements correctly describe the relationship between a weak acid or base and its conjugate base or acid? Select all that apply.

The stronger a base is, the more strongly the formation of its conjugate acid is favored. The weaker an acid is, the stronger its conjugate base will be.

Which of the following statements are correct about conjugate acids and bases?

Water is a weak conjugate acid. Iodide is a weak conjugate base. Acetate is a strong conjugate base.

When calculating the pH of a weak acid or weak base solution, we assume that the [H3O+] or [OH-] due to ionization is negligible. When is this assumption justified?

When the acid/base shows less than 5% ionization