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