ch 16 Flashcards
Carbonic acid is a diprotic acid, H2CO3, with Ka1 = 4.2 × 10–7 and Ka2 = 4.8 × 10–11 at 25°C. The ion product for water is Kw = 1.0 × 10–14 at 25°C. What is the OH– concentration of a solution that is 0.39 M in Na2CO3?
a.
Which acid–base reaction results in acidic solution?
HBr(aq) + KOH(aq) → H2O() + KBr(aq)
HNO3(aq) + LiOH(aq) → H2O() + LiNO3(aq)
HCl(aq) + KOH(aq) → H2O() + KCl(aq)
H2SO4(aq) + CsOH(aq) H2O() + CsHSO4(aq)
HF(aq) + RbOH(aq) H2O() + RbF(aq)
d.
What is the hydroxide-ion concentration in a 0.10 M solution of Na2CO3? For carbonic acid, Ka1 = 4.2 × 10–7 and Ka2 = 4.8 × 10–11. (Kw = 1.0 × 10–14)
4.6 × 10–3 M
2.0 × 10–4 M
4.9 × 10–5 M
4.2 × 10–9 M
2.2 × 10–6 M
a.
Which of the following substances is never a Brønsted-Lowry acid in an aqueous solution?
sodium dihydrogen phosphate, NaH2PO4(s)
sodium acetate, NaCH3CO2(s)
ammonium nitrate, NH4NO3(s)
hydrogen bromide, HCl(g)
sodium bicarbonate, NaHCO3(s)
B
Which of the following statements is/are consistent with the Brønsted–Lowry concept of acids and bases?
1. A conjugate acid–base pair consists of two species that may differ by one proton.
2. A Brønsted–Lowry base is defined as a hydroxide ion donor.
3. Brønsted–Lowry acid-base reactions are restricted to only aqueous solutions.
1 only
2 only
3 only
1 and 2
1, 2, and 3
not b or d. or c.
Which of the following species is the strongest acid in an aqueous solution?
not a. Or e or c
Probably b but answer bank wrong
Says it’s d
The complete reaction of an acid and base is as follows.
HNO3(aq) + LiOH(aq) → H2O() + LiNO3(aq)
What is the equilibrium constant for the net ionic reaction at 25 °C?
d.
Which of the following statements is INCORRECT?
H3PO4 is a stronger acid than H2PO4−.
HClO3 is a stronger acid than HClO2.
HNO3 is a stronger acid than HNO2.
[Fe(H2O)6]2+ is a stronger acid than [Fe(H2O)6]3+.
HOCl is stronger acid than HOBr.
d.
Which of the following statements is true of the acid–base properties of common cations and anions in aqueous solutions?
The anions that are conjugate bases of strong acids are strong bases.
The acid–base behavior of anions of polyprotic acids is independent of the extent of deprotonation.
Alkali metal and alkali earth cations have no measurable effect on solution pH.
Basic anions are conjugate bases of acidic cations.
Basic cations are conjugate bases of weak acids.
c
Identify from the following list of molecules and ions which behave as Lewis acids: CO2, NH3, BCl3, and Fe3+.
CO2 and NH3
NH3 and BCl3
CO2 and Fe3+
CO2, BCl3, and Fe3+
CO2, NH3, BCl3, and Fe3+
d.
What is the pH of a solution prepared by dissolving 0.523 g of NaOH(s) in 5.50 L of water? (Kw = 1.01 × 10–14)
d
Calculate the pH of a 1.7 M solution of H2A (Ka1 = 1.0 × 10–6 and Ka2 is 1.0 × 10–10).
b.
The autoionization of pure water, as represented by the equation below, is known to be endothermic (ΔrΗ > 0). Which of the following correctly states what occurs as the temperature of pure water is raised?
H2O(l) + H2O(l) H3O+(aq) + OH–(aq) ΔrΗ > 0
e.
What is the hydroxide-ion concentration of a 0.190 M sodium oxalate (Na2C2O4) solution? For oxalic acid (H2C2O4), Ka1 = 5.6 × 10–2 and Ka2 = 5.1 × 10–5. (Kw = 1.01 × 10-14)
a.
The concentration of H3O+in a solution is 5×10–4M at 25°C. What is its hydroxide-ion concentration? (Kw= 1.01×10–14)
5×10–4M
2×10–10M
3×10–10
4×10–10M
2×10–11M
Not c or d. or b.
Which of the following molecules or ions is the strongest acid?
CH3CO2–
CH3CO2H
CFH2CO2H
CF2HCO2H
CF3CO2H
e.
What is the pH of the solution that results from mixing 75 mL of 0.50 M NH3(aq) and 75 mL of 0.50 HCl(aq) at 25°C? (Kbfor NH3= 1.8×10–5)
0.60
2.67
4.74
4.93
9.26
Not b or a. or c.
What is the hydronium-ion concentration in a solution formed by combining 750mL of 0.10MNaOH with 250mL of 0.30MHCl?
NaOH(aq) + HCl(aq)→NaCl(aq) + H2O(l)
0.075 M
1.7×10–13M
1.0×10–7M
0.30 M
0.10 M
C
What is the hydroxide-ion concentration in a solution formed by combining 200.mL of 0.15MHCl with 300.mL of 0.090MNaOH at 25°C?
HCl(aq) + NaOH(aq)→NaCl(aq) + H2O(l)
1.7×10–13M
0.090M
1.7×10–12M
0.054M
1.0×10–7M
Not b
Given the following equilibrium constants,
Ka(HSO4–) = 1.2×10–2
Kb(CH3CO2–) = 5.6×10–10
Kw= 1.00×10–14
determine the equilibrium constant for the reaction below at 25°C.
HSO4–(aq) + CH3CO2–(aq)SO42–(aq) + CH3CO2H(aq)
6.7×10–12
2.1×10–7
1.5×10–3
6.7×102
2.1×107
d.
What is the equilibrium constant for the following reaction,
HCO2H(aq) + CN–(aq)HCO2–(aq) + HCN(aq)
and does the reaction favor the formation of reactants or products? The acid dissociation constant,Ka, for HCO2H is 1.8×10–4and the acid dissociation constant for HCN is 4.0×10–10.
D
Which of the following is the correct equation for the reaction of ammonia in water?
NH3(aq) + H2O(l)NH4+(aq) + OH−(aq)
NH3(aq) + H2O(l)NH2−(aq) + H3O+(aq)
NH3(aq) + H3O+(aq)NH4+(aq) + H2O(l)
NH3(aq) + OH−(aq)NH2−(aq) + H2O(l)
NH3(aq) + H2O(l)NH2−(a
a,
Aqueous solutions of ammonia (NH3) and hydrogen cyanide (HCN) react to produce ammonium cyanide, (NH4CN) according to the following equilibrium reaction.
NH3(aq) + HCN(aq)DNH4+(aq) + CN−(aq)
Given the following equilibrium constants, which statement best describes the reaction once equilibrium is established? (Kw= 1.01×10-14)
NH4+Ka= 5.6×10-10HCNKa= 4.0×10-10
The reaction is product favored.
The reaction is reactant favored.
The reaction is neither product
b
What is the pH of 0.010 M aqueous hypochlorous acid? (Kaof HOCl = 3.5×10–8)
2.00
4.50
4.73
6.54
7.45
C
What is the pH of the final solution when 25 mL of 0.021MHCl has been added to 35mL of 0.035MHCl at 25°C?
3.4
1.9
1.5
2.8
3.5
C
What is the pH of the solution which results from mixing 50.0 mL of 0.30 M HF(aq) and 50.0 mL of 0.30 M NaOH(aq) at 25°C? (Kaof HF = 7.2×10–4)
1.98
5.84
8.16
10.85
C
What is the conjugatebaseof HPO43-in aqueous solution?
not possible
PO43–
HPO42−
H2PO4−
H3PO4
B
The pH of aqueous 0.10 M pyridine (C5H5N) ion is 9.09. What is theKbof this base?
8.0×10–10
1.5×10–9
9.0×10–6
1.6×10–5
1.2×10–5
B
Which is the stronger Brønsted-Lowry acid, Fe(H2O)62+or Fe(H2O)63+? Explain.
The second one is the stronger acis because it has a larger Ka value.
Which of the following is the correct hydroxide ion (OH–) concentration of an aqueous solution with a pH of 2.77? (Kw= 1.01×10–14)
a.
What is the pOH of 0.074 M HI(aq) at 25°C? (Kw= 1.01×10–14)?
2.60
12.87
11.40
15.13
1.13
b.
The chemical equations below show the reaction of Al(OH)3as a Lewis acid and as a Lewis base, respectively.
Al(OH)3(s) + OH–(aq)Al(OH)4–(aq)
Al(OH)3(s) + 3 H3O+(aq)Al3+(aq) + 3 H2O()
Substances that can behave as either Lewis acids or bases are called ________ substances.
amphoteric
Which of the following expressions is not equivalent to the formula of pH?
e.
According to the Brønsted-Lowry definition, abase
e
Which equation depicts the hydrogen phosphate ion behaving as a Brønsted–Lowry base in water?
a
Which of the following is true of the equilibrium constants (K,Ka,Kb)?
a.
When a Lewis acid combines with a Lewis base, the base supplies both the electrons to the bond. This type of chemical bond is called a(n) _____ covalent bond.
Coordinate
A solution has a hydroxide ion concentration of 0.0040M. Calculate the pOH of the solution at 25°C. (Kw= 1.01×10–14)
b
Consider theKavalues for the following acids:
Cyanic acid, HOCN, 3.5×10–4
Formic acid, HCHO2, 1.7×10–4
Lactic acid, HC3H5O3, 1.3×10–4
Propionic acid, HC3H5O2, 1.3×10–5
Benzoic acid, HC7H5O2, 6.3×10–5
Which of the following isthestrongestacid?
a
H3PO3is a diprotic weak acid. What is the balanced equilibrium defined asKb2of H3PO3?
Not a
What is the H3O+concentration in 0.0072MNaOH(aq) at 25°C? (Kw= 1.01×10–14)
a.
All of the following compounds are acids containing chlorine. Which compound is the weakest acid?
b
Which of the following speciescannotact as a Lewis base?
not a or b.
At 50°C the autoionization constant for pure water,Kw, is. What is the H3O+concentration in pure water at 50°C?
Not b
What is the equilibrium concentration of H2C2O4in a 0.170 M oxalic acid, H2C2O4, solution? For oxalic acid,Ka1= 5.6×10–2andKa2= 5.1×10–5.
a.
Which are the Brønsted–Lowry bases in the following equilibrium?
CH3COO–(aq) + H2O(l)CH3COOH(aq) + OH–(aq)
e.
Consider the reaction CO32-(aq) + H2O(l)HCO3-(aq) + OH–(aq).Kbfor CO32-is 2.1×10–4at 25°C. What isKafor the HCO3-ion at 25°C?
b
Which of the following equations shows that isoquinoline, C9H7N, behaves as a Brønsted-Lowry base in water?
c.
Given the following acid dissociation constants:
Ka(H3PO4) = 7.5×10–3
Ka(NH4+) = 5.6×10–10
Determine the equilibrium constant for the reaction below at 25°C.
H3PO4(aq) + NH3(aq)NH4+(aq) + H2PO4−(aq)
d.
Which of the following is the correct hydronium ion ,H3O+,concentration of 0.0013M KOH(aq) at 25°C? (Kw= 1.01×10–14)
Not c or d. or b.
What is the pH of a 0.42 M solution of sodium propionate, NaC3H5O2, at 25°C? (propionic acid, HC3H5O2, is monoprotic and has a Ka = 1.3 × 10–5 at 25°C.. Kw = 1.01 × 10-14 )
e.
Calculate the pH of the following aqueous solution:
0.17 M H2S (pKa1= 7.00; pKa2= 12.89)
C
The H3O+ concentration of a solution is 5.9 × 10–6 M. What is the pH of the solution?
d.
When a Lewis acid and a Lewis base combine, the product may be referred to as an acid-base ________
Adduct
The pH of a solution at 25 °C in which [OH–] = 3.9×10–5M is _____. (Kw= 1.01×10–14)
Not b
What is the OH–concentration of an aqueous solution with a pH of 9.83? (Kw= 1.01×10–14)
What is the pH of a solution prepared by dissolving 0.459 L of HCl(g), measured at STP, in enough water such that the total volume of the solution is 5.50L? (R=0.0821L·atm/K·mol)
a.
What volume of water must be added to 14.4mL of a pH 2.0 solution of HNO3in order to change the pH to 4.0?
Not b or d. or a.
H3PO3is a diprotic weak acid. What is the balanced equilibrium defined asKb2of H3PO3?
What is the equilibrium pH of an initially 0.83 M solution of the monoprotic acid 3-chloropropanoic acid at 25°C (Ka=)?
What is the OH– concentration of an aqueous solution with a pH of 9.83? (Kw = 1.01 × 10–14)
Not a
H3PO3is a diprotic weak acid. What is the balanced equilibrium defined asKb2of H3PO3?
D
Given that Ka for the weak acid HA is 3.49 × 10–8, calculate K for the reaction of HA with OH–.
HA(aq) + OH−(aq) D A−(aq) + H2O()
b.
An aqueous solution with a pH of 10.60 is diluted from 1.0 L to 2.0 L. What is the pH of the diluted solution?
c.
Calculate the pH of a 0.09 M solution of ascorbic acid (Ka1 = 7.9 × 10–5; Ka2 is 1.6 × 10–12).
B
What is the equilibrium pH of a 0.700 M solution of H3PO4(aq)? (Ka1 = 7.5 × 10–3, Ka2 = 6.2 × 10–8, Ka3 = 4.8 × 10–13)
Not e or d or b.
Which of the following ionic compounds forms a neutral aqueous solution at 25 °C?
b.
What is Ka at 25°C for the following equilibrium given Kb (CH3NH2) = 4.4 × 10–4 at 25°C.?
CH3NH3+(aq) + H2O(l) CH3NH2(aq) + H3O+(aq)
Not c or b.
What is the pH of a 0.33 M solution of methylamine (CH3NH2,Kb= 4.4×10–4) at 25oC? (Kw= 1.01×10-14)
Not b or a.
Molecules or ions that can alternately behave as either a Brønsted-Lowry acid or base are called
Group of answer choices
polyanions.
hydronium ions.
polyprotic acids or bases.
conjugate acids or bases.
amphiprotic.
e.
What is the equilibrium pH of an initially 4.9 M solution of hypoiodous acid, HOI, at 25°C (Ka = ; Kw = 1.01 × 10-14)?
a.
Which of the following is the correct hydroxide ion concentration in 0.48 M CH3CO2–(aq)? (Kb of CH3CO2– = 5.6 × 10–10)
not c. or b.
What is the H3O+ concentration in 0.0055 M Ba(OH)2(aq) at 25 °C? (Kw = 1.01 × 10–14)?
not a. or b.
Which of the following substances is never a Brønsted-Lowry base in an aqueous solution?
d.
Which of the following pairs of species is not a conjugate acid–base pair?
b.
What is the conjugate base of [Fe(H2O)6]3+(aq)?
d.
Which equation depicts aqueous hydrogen sulfide behaving as a Brønsted-Lowry base in water?
c.
Hydrofluoric acid has a pKa value of 3.14. What is the value of pKb for fluoride ion?
d.
At 25 °C, all of the following ions produce an acidic solution, except ____.
c.
A 0.10 M solution of a weak monoprotic acid has a hydronium-ion concentration of 8.0 × 10–4 M. What is the acid-ionization constant, Ka, for this acid?
e.
What is the hydronium-ion concentration of a 0.25 M solution of HCN (Ka = 4.9 × 10–10) at 25°C?
d.
Which of the following is the strongest acid in aqueous solution?
b
What is the equilibrium pH of an initially 0.83 M solution of the monoprotic acid 3-chloropropanoic acid at 25°C (Ka = )?
a.
Consider the reaction CO32-(aq) + H2O(l) HCO3-(aq) + OH–(aq). Kb for CO32- is 2.1 × 10–4 at 25°C. What is Ka for the HCO3- ion at 25°C?
b.
The equilibrium constant, Ka,for a monoprotic acid (benzoic acid) is 6.3 × 10–5. Which of the following is the correct value of Kb for the benzoate ion, the conjugate base of benzoic acid?
not d. or c.
Which one of the following aqueous solutions will have a pH of 2.00 at 25 °C? (Kw = 1.01 × 10–14)
not d. or c.
Which of the following statements about the reaction below is correct?
HCO3–(aq) + H2O() CO32–(aq) + H3O+(aq)
b.
Rank H3PO4, H2PO4–, and HPO42– in order of increasing acid strength.
a.
All of the following species behave as Lewis acids EXCEPT ____.
not c. or b.
What is the pH of a 0.046 M HClO4(aq) at 25 °C? (Kw = 1.01 × 10–14)
not c. or b. or e.
A molecule that can behave as either a Brønsted-Lowry acid or base is termed ________.
amphoteric
Consider the Ka values for the following acids:
Cyanic acid, HOCN, 3.5 × 10–4
Formic acid, HCHO2, 1.7 × 10–4
Lactic acid, HC3H5O3, 1.3 × 10–4
Propionic acid, HC3H5O2, 1.3 × 10–5
Benzoic acid, HC7H5O2, 6.3 × 10–5
Given initially equimolar solutions of each weak acid, which solution will have the highest pH once equilibrium is established?
c.
Which of the following species is amphiprotic in aqueous solution?
e
Which of the following does not behave as an amphiprotic species in water?
not c. or b.
In the reaction
CaO(s) + CO2(g) → CaCO3(s),
not c.
When a Lewis acid and a Lewis base combine, the product may be referred to as an acid-base ________.
adduct
Which of the following ionic compounds does not produce a basic aqueous solution at 25 °C?
not c.
At 50°C the autoionization constant for pure water, Kw, is . What is the H3O+ concentration in pure water at 50°C?
d.
Given the equilibrium constants for the equilibria,
H2O(l) H3O+(aq); K =
2CH3COOH(aq) + 2H2O(l) 2CH3COO−(aq) + 2H3O+(aq); K =
determine Kc for the following equilibrium.
CH3COOH(aq) + NH3(aq) CH3COO−(aq) + NH4+(aq)
not b.
