s

Some salts, such as NH4NO2NH4NO2, contain both an acidic cation and a basic anion.

acidic; basic; neutral

The measured pH of a solution is usually not the same as that calculated from [H+] unless _____ replaces concentration to account for nonideal behavior.

activity

For real solutions, pH is defined as the negative logarithm of the _____ of the H+ ion. For dilute solutions, we use _____ in place of activity.

activity, concentration

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

anion; cation

Water functions as a(n) ______ n reactions with stronger acids, and functions as a(n) _____ n reactions with stronger bases.

base ,acid

An acid donates a proton to form its conjugate ___ base , Correct Unavailable, which therefore has one less_______ , Correct Unavailable atom and one more ______ , Correct Unavailable charge than its acid.

base h NEGATIVE

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

base stronger

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

A Bronsted-Lowry acid is a proton _____ and must therefore contain at least one ionizable _____ atom in its formula.

donor; hydrogen

The ______ of ionized HA molecules increases as a weak acid solution is diluted.

%

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

0.00010 M

Calculate κbκb of a weak base with a pH 11.21 and an initial concentration of [B] = M.

κb = 1.32 × 10−5

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

% ionization = [H+]eq[HA]0[H+]eq[HA]0 x 100

Which of the following CH3COOH/CH3COONa buffer systems has the highest buffer capacity? Assume that equal volumes of the solutions are mixed in each case.

0.100 M CH3COOH/0.100 M CH3COONa

Which of the following can NOT be used as an acid-base buffer solution? Select all that apply.

0.5 M HNO3 and 0.5 M NaNO3 0.3 M HCl and 0.3 M NaOH

Which of the following NH3/NH4+ buffer systems has the highest buffer capacity? Assume that equal volumes of the solutions are mixed in each case.

1.00 M NH3/1.00 M NH4+

30.0 mL of a 0.15 M solution of the weak acid HClO is titrated with 0.20 M NaOH. Which of the following options correctly reflect how to calculate the pH after the addition of 16.5 mL of NaOH? Select all that apply. (The equivalence point has not yet been reached.) Ka for HClO is equal to 3.0 x 10-6.

1.2 x 10-3 moles of HClO remain in solution. 3.3 x 10-3 moles of OH- have been added. pH = -log(3.0 x 10-6) + log3.3x10-31.2x10-3

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%

A 0.15 M solution of butanoic acid, CH3CH2CH2COOH (or C3H7COOH), contains 1.51 x 10-3 M H3O+. What is the Ka of butanoic acid?

1.5 x 10-5

The pH scale is a logarithmic scale, meaning that a solution with a pH of 1.00 has a concentration of hydronium (H3O+) _____ times _____ than a solution with a pH of 3.00.

100; greater

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

11.45

Which of the options given expresses the solution to the following calculation to the correct number of significant figures? pH = -log(1.12 x 10-12)

11.951

If the molarity of a solution is given to 2 significant figures (e.g., 0.15 M), the pH value will be reported to 2Blank 1Blank 1 2 , Correct Unavailable places after the decimal.

2

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

Calculate the Ka value for the anilium ion (C6H5NH3+) if Kb for aniline (C6H5NH2) is 4.0 x 10-10.

2.5 x 10-5

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

Which of the following options correctly describes the function of an acid-base buffer?

A buffer minimizes changes in pH when acid or base is added to the solution.

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 options correctly describe the behavior of strong and weak acids (general formula HA) in aqueous solution? Select all that apply.

A weak acid is a weak electrolyte. The solution of a strong acid will have a negligible concentration of unionized HA molecules.

Select the statements that correctly describe the aqueous solution of a metal cation. Select all that apply.

An aqueous solution containing small, highly charged metal cations will be acidic. A positively charged metal ion draws electron density from the O-H bonds of H2OH2O molecules, releasing H+H+ ions. The presence of large metal cations with low charges does not impact the pH of aqueous solutions.

Which of the following structural characteristics must be present for a species to act as a Bronsted base?

An atom that has a lone pair of electrons

Which of the following options correctly describe how to calculate the pH at various points during the titration of a weak acid against a strong base? Select all that apply.

At the equivalence point, [A-] = initialmolesofHAtotalvolumeinitialmolesofHAtotalvolume. At the equivalence point, the pH calculation is based on the reaction of the conjugate base A- with H2O. The initial [H3O+] is calculated from [HA]init and Ka.

Select all that apply Which of the following statements correctly describe the relationship between the species in the reaction shown? Select all that apply.

B and D are a conjugate acid-base pair. The base in the forward reaction is CH3NH2. HSO3- is the conjugate acid of SO32-.

Which of the following options represent heterogeneous equilibria? Select all that apply.

BaSO4 (s) ⇌ Ba2+ (aq) + SO42- (aq) CaF2 (s) ⇌ Ca2+ (aq) + 2F- (aq) 2H2O (l) ⇌ 2H2 (g) + O2 (g)

What is the predominant factor in determining the acid strength of binary hydrohalic acids?

Bond enthalpy

Which of the following statements correctly describe the acid-base properties of a 0.10-M solution of ammonium cyanide (NH4CN)? Select all that apply. Ka of NH4+ = 5.6 x 10-10 and Kb of CN- = 1.8 x 10-5.

Both NH4+ and CN- will hydrolyze (react with water) in aqueous solution. The solution will be basic. CN- will behave as a base when it reacts with water.

In what way is the titration curve for a weak base-strong acid titration similar to the titration curve for a weak acid-strong base titration?

Both have a buffer region before the equivalence point is reached.

Buffer______is a measure of the ability of a buffer to maintain the pH following the addition of strong acid or base.

CAPACITY

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.

Which of the following options correctly describe the structural characteristics of strong and weak bases? Select all that apply.

Compounds that contain electron-rich N are weak bases. Soluble hydroxides are strong bases.

Which of the following quantities must be known in order to calculate the pH of an acid-base buffer solution using the Henderson-Hasselbalch equation? Select all that apply.

Concentration of weak acid Concentration of conjugate base Ka of weak acid or Kb of weak base

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+].

True or false: For any acid-base reaction, Ka x Kb = Kw for the reacting acid and base.

False

The autoionization of water is a process whereby water ionizes to a small extent to form____ asn ____

H and OH

Which statement correctly explains why even distilled and deionized H2O contains some ions?

H+ can be transferred from one H2O molecule to another, forming H3O+ and -OH ions.

The hydrogen phosphate ion, HPO42-, can act as both a Bronsted acid and Bronsted base in water. Select all the options that correctly describe the reaction that occurs when HPO42- acts as a Bronsted base in water.

H2PO4- is one of the products. OH- is one of the products. H2O acts as the Bronsted acid.

Which of the following is NOT a conjugate acid-base pair? Multiple choice question

H2PO4-/PO43-

Which statement best explains the trend in acid strength: H2SO4 > H2SO3 > H2SeO3?

H2SO4 is stronger than H2SO3 because it has more O atoms.

Which of the following formulas can be used to represent the proton in aqueous solution? Select all that apply.

H3O+ H+

The pH at the equivalence point is < 7.00 for a weak base - strong acid titration. This is because the conjugate acid of the weak base hydrolyzes to produce ______ and re-form the weak base

H3O+H3O+ ions

Which of the following statements correctly describes the relative strength of binary acids? Select all that apply.

HBr is a stronger acid than HCl because its value for bond enthalpy is lower. HI is the strongest hydrohalic acid.

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, Ka= 4.9 x 10-10 CH3COOH Ka= 1.8 x 10-5 HFKa= 7.1 x 10-4

Which of the following conjugate acid-base pairs is the best choice to prepare a buffer of pH 3.50?

HCOOH/HCOONa (pKa of HCOOH = 3.74)

Which of the following statements correctly explain the relative strengths of the oxoacids shown: HBrO < HClO < HClO2 < HClO3? Select all that apply.

HClO3 is stronger than HClO2 because HClO3 has more O atoms. HBrO is weaker than HClO because Br is less electronegative than Cl.

Which of the following species are weak acids? Select all that apply.

HF NH4+ HNO2

Select all the statements that correctly describe the acid-base behavior of H2O

In aqueous HCl, water acts as a Bronsted base. Water is amphoteric. In aqueous NH3, water acts as a Bronsted acid.

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

KCH3COO NaCN

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.

In order to determine whether a solution of NH4C2H3O2 is acidic, basic, or neutral, what two values could be compared?

Ka of NH4+ Kb of CH3COO-

25.0 mL of 0.250 M HCl is titrated with a 0.125 M solution of the weak base aniline (C6H5NH2; Kb = 3.80 x 10-10). The equivalence point is reached when 50.0 mL of base has been added. Which of the following options correctly reflect the steps required to calculate the pH at the equivalence point? Select all that apply.

Ka of the conjugate acid C6H5NH3+ = 2.63 x 10-5 [C6H5NH3+] at the equivalence point = 6.25x10-30.025+0.050L6.25x10-30.025+0.050L = 8.33 x 10-2 M pH = 2.82

Select the statement that correctly describes polyprotic acids.

Ka1 >> Ka2 >> Ka3

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

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

Select the statement that correctly explains why it is reasonable to assume that for a weak acid, [HA] at equilibrium is approximately equal to [HA]init under most circumstances.

Most molecules of the weak acid remain unionized at equilibrium.

Select the correct explanations why the pH of a properly chosen buffer solution changes relatively little when strong acid or base is added to it. Select all that apply

Most of the excess H3O+ or OH−H3O+ or OH- is absorbed by the resulting shift in equilibrium. The ratio [A−][HA][A-][HA] changes relatively little due to the shift in equilibrium.

Which of the following combinations could be used in an acid-base buffer system? Select all that apply.

NH3 /NH4Cl CH3COOH/NaCH3COO HNO2 /KNO2

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.

What is the conjugate base of HNO2 if it reacts as a Bronsted acid in H2O?

NO2-

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.

NO3- I- Cl-

Which is(are) the ionizable proton(s) in the organic formic acid, HCOOH?

Only the hydrogen bonded to oxygen is ionizable.

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

Polyprotic acids are generally weak acids. A polyprotic acid has more than one ionizable proton.

Which of the following statements correctly describe salt hydrolysis?

Salt hydrolysis causes the pH of the resulting solution to be above or below 7.00. Both the anion and the cation of a water-soluble salt may interact with water. The ions produced by dissociation of a salt in water react with H2O.

Which of the following options correctly describe the behavior of acids and bases in aqueous solution? Select all that apply.

Strong bases ionize completely in aqueous solution. A weak acid ionizes to a limited extent in aqueous solution. Strong acids and bases are electrolytes.

Consider two solutions of the weak acid HCN, one with concentration 0.10 M and one with concentration 0.010 M. Select the statements that correctly describe these solutions.

The 0.10 M solution will have a higher [H3O+]. The 0.010 M solution will have a higher percent ionization.

Which of the following are valid assumptions used in solving weak-acid equilibrium problems? Select all that apply.

The [H3O+] from water is negligible. For very weak acids (Ka < 10-4) at concentrations greater than 0.10 M, [HA]eqm ≈ [HA]0, the original acid concentration.

Which of the following descriptions are correct for an acid-base indicator? Choose all that apply.

The color of the indicator changes over a specific, fairly narrow, pH range. Only a small amount of indicator is needed during a titration.

Why does the equivalence point for a weak base-strong acid titration occur at a pH < 7.00?

The conjugate acid of the weak base reacts with H2O to give a solution with pH < 7.00.

Which statement most clearly explains the relationship between an acid and its conjugate base?

The conjugate base of a weak acid will react with water to a greater extent than the acid itself does.

Which of the following options correctly describe the differences between the titration curve for a weak acid-strong base titration and a strong acid-strong base titration? Select all that apply.

The curve for the weak acid-strong base titration rises gradually through a buffer region before the steep rise to the equivalence point. The pH at the equivalence point is above 7.00 for the weak acid-strong base titration

Which of the following statements correctly describe the titration curve for the titration of a strong acid with a strong base? Select all that apply.

The equivalence point is at a pH of 7.00. The pH rise is very steep close to the equivalence point of the titration.

Select the correct statements of the differences between the titration curve of a weak base with a strong acid to that of a weak acid titrated with a strong base. Select all that apply.

The equivalence point of a weak base-strong acid titration curve will have a pH < 7.00. The weak base-strong acid titration curve begins at a pH above 7.00.

Consider a buffer solution consisting of 0.35 M HNO2 and 0.50 M KNO2, which has an initial pH of 3.50 (Ka for HNO2 = 4.5 x 10-4). If 0.03 mol of HCl are added to 1.0 L of this solution, which of the following options correctly reflect the steps required to calculate the change in pH? Select all that apply.

The final pH = 3.44. [NO2-] after the addition of HCl is equal to 0.47 M. [H3O+] prior to the addition of HCl ≈ 4.5×10-4×0.350.504.5×10-4×0.350.50.

Which of the following factors will affect the relative strength of oxoacids? Select all that apply.

The number of O atoms attached to the central nonmetal atom The electronegativity of the central nonmetal atom

Select the correct statements about the equivalence point for a weak acid-strong base titration. Select all that apply.

The pH is the result of the conjugate base reacting with water. The pH is greater than 7.00.

Calculate and compare the pH values for 0.10 M solutions of NH4Br (Ka 5.6 x 10-10) and Al(NO3)3 (Ka 1.3 x 10-5). Which of the following statements correctly describe the acidity of these solutions? Select all that apply.

The pH of the Al(NO3)3 solution is 2.94. The NH4Br solution has a higher pH than the Al(NO3)3 solution.

Which of the following statements accurately describe Bronsted-Lowry acid-base reactions? Select all that apply.

The reactants and products contain an acid and a base. Some species can act as either an acid or a base depending on the other species present.

With reference to the table provided, compare the relative strengths of the acids and bases involved in the reaction shown, and predict the preferred direction of reaction. HCOOH (aq) + F- (aq) ⇌ HCOO- (aq) + HF (aq)

The reaction favors the reactants. HF is a stronger acid than HCOOH.

Calculate [OH-] in a solution that has [H3O+] = 6.7 x 10-2 M. Is the solution acidic or basic?

The solution is acidic. 1.5 x 10-13 M

Calculate [H3O+] in a solution with a [OH-] = 3.0 × 10-4 M. Is the solution acidic or basic?

The solution is basic. 3.3 × 10-11 M

Which of the following options correctly describe a solution with a pH = 8.00? Select all that apply.

The solution is basic. [OH-] > [H3O+]

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

The solution will have a pH > 7.00. CN+(ag) + H2O(l) ⇋ OH+(ag) + HCN(ag)

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

An acid-base reaction occurs when one species loses a proton and another species simultaneously gains a proton. An acid-base reaction can therefore be viewed as a proton- Process

Transfer

Which of the following options correctly represent the relationship between [H3O+] and [OH-] in aqueous solutions at 25oC? Select all that apply.

[H3O+] = 1.0 × 10-14[OH-]1.0 × 10-14[OH-] [H3O+][OH-] = 1.0 x 10-14

Calculate the pH and [H3O+] of a 0.080 M solution of NaOH.

[H3O+] = 1.3 x 10-13 M pH = 12.90

Which of the following options shows the correct mathematical operation required to calculate [H3O+] for a solution with a pH of 3.52?

[H3O+] = 10-3.52 = 3.0 x 10-4 M

Which of the following gives the correct mathematical operation required to calculate the [H3O+], given a pH of 5.0?

[H3O+] = 10-5.0

Consider a 0.10 M CH3COOH solution (Ka = 1.8 x 10-5). Which statement is correct about this system at equilibrium?

[H3O+] = [CH3COO-]

Consider a buffer solution consisting of 0.40 M NaCNO and 0.40 M HCNO, which has an initial pH of 3.46. Ka for HCNO = 3.5 x 10-4. If 10. mL of a 2.0 M NaOH solution are added to 1.0 L of this buffer, select the options that correctly reflect the steps required to calculate the change in pH. Select all that apply.

[H3O+]new = 3.5 x 10-4 x 0.380.420.380.42 pHnew = -log(3.17 x 10-4) = 3.50

Select the correct options for a weak acid, HA, at equilibrium. Select all that apply.

[HA]equilibrium ≈ [HA]initial

A 0.10 M NH4Cl solution is found to be acidic. Select the statement that correctly represents the relative [H3O+] and [OH-] in this solution.

[OH-] < [H3O+]

A Bronsted-Lowry base is a proton _____. In order for a compound to act as a Bronsted base it must possess a(n) _____.

acceptor, lone pair of electron

According to _____ HI should be the strongest binary hydrohalic acid. In contrast, according to _____ HF should be the strongest binary hydrohalic acid. Since HI is the strongest binary hydrohalic acid, the predominant factor in determining acid strength of these species is _____.

bond enthalpy, polarity, bond enthalpy

In a Bronsted-Lowry acid-base reaction, the acid reacts to form its _______ _____ and the base will form its _____ ______

conjugate base, conjugate acid

In an aqueous solution at a given temperature, the product [H3O+][OH-] has a _____ value. This product is equal to _____ at 25oC.

constant, 1.0 x 10-14

Given the ion-product constant for water Kw = [H3O+][OH-], as the concentration of hydronium increases the concentration of hydroxide _____.

decreases

An acid can be defined as a substance that loses one or more H+ ions when dissolved in water. An H+ ion is a hydrogen atom that has lost a(n) and is therefore just a(n) . The H+ ion is not an isolated ion, but interacts strongly with H2O to produce the ion, which has the formula H3O+.

electron proton hydronium

The _____ point of a titration is the point at which the indicator changes color. The indicator is chosen so that the color change occurs at a pH as close as possible to the pH of the _____ point.

end; equivalence

For a weak acid-strong base titration the pH at the equivalence point is ______.

greater than 7.00

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

higher; larger

When an ionic compound dissociates in water, the separated ions may react with H2O to produce H3O+ or OH- ions. This process, known as salt hydrolysisBlank 1Blank 1 hydrolysis , Correct Unavailable, may affect the pHBlank 2Blank 2 pH , Correct Unavailable of the salt solution.

hydrolysis, pH

Oxoacids have the general formula illustrated, where the number of bonds to the central element E can vary. For the same element E, acid strength will _____ as the number of O atoms increases. For the same number of O atoms, acid strength increases as the _____ of element E increases.

increase; electronegativity

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

increases

Basic solutions have a _____ pOH than acidic solutions.

lower

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 higher the pH value, the _____ the [H3O+] and the _____ acidic the solution will be.

lower; less

Calculate the pH and [OH-] of a solution of a 1.5 M solution of HCl.

pH = -0.18 [OH-] = 6.7 × 10-15 M

Which of the following mathematical relationships are correct for an aqueous solution at 25oC? Select all that apply.

pH = -log[H3O+] pOH + pH = 14.00

Consider a buffer made by combining equal volumes of 0.15 M CH3COOH and 0.32 M NaC2H3O2. What is the pH of this buffer if the Ka for CH3COOH is 1.8 x 10-5?

pH = 5.07

Slove for the pH of a 0.22 M CH3NH3CH3NH3Br solution. κb for CH3NH2 is 4.4 × 10−4κb for CH3NH2 is 4.4 × 10-4.

pH = 5.65

Solve for the pH of a 0.22 M NaF solution. κaκa for HF is 6.8 ×× 10−410-4.

pH = 8.25

The degree of ionization for a weak monoprotic acid HA is given by the expression [H+]eq[HA]0[H+]eq[HA]0 x 100. This is called the percentBlank 1Blank 1 percent , Correct Unavailable ionization and is a measure of acid strength.

percent

In a homogeneous solution equilibrium system, all the reactants and products are in the same

phase

The reaction HNO2 (aq) + NH2- (aq) ⇌ NH3 (aq) + NO2- (aq) favors the formation of the _____ because NH2- is a _____ base than NO2-.

products, stronger

Acid ionization is represented by the general equation HA + H2O (l) ⇌ H3O+ (aq) + A- (aq) For a strong acid the equilibrium lies far to the _____ and [H3O+] is much _____ than [HA]. For a weak acid, on the other hand, the equilibrium lies far to the _____ and [H3O+] is much _____ than [HA].

right, higher, left, lower

When a strong acid or base is added to a buffer system, there is a ______ change in the [HA][A−][HA][A-] ratio and thus a ______ change in pH.

small; small

The two factors that influence the extent of ionization of an acid are the

strength and polarity

Acetic acid, CH3COOH, is a _____ acid compared to NH3; hence, CH3COO- is a ____ base than the amide ion, NH2-. (Refer to the table of acids and bases provided.)

stronger, weaker

An indicator is a(n) weakBlank 1Blank 1 weak , Correct Unavailable organic acid that has a different color than its conjugateBlank 2Blank 2 conjugate , Correct Unavailable base. Each indicator changes color over a specific, narrow pHBlank 3Blank 3 pH , Correct Unavailable range.

weak conjugate PH

A(n) , acid is one that ionizes only slightly in water, whereas a(n) , acid ionizes completely into ions.

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 _____. HA + H2O ⇌ H3O+ + A-

weaker, conjugate base