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WorksheetsAcid-Base Buffer II
Total questions: 27
Worksheet time: 42mins
What are the products of the neutralization shown below?
Ca(OH)2 + H2CO3 -->
H2O + Ca2CO3
CaO + CO3
H2O + CaCO3
CO2 + CaH2
The definition of a buffer is
a solution that resists significant changes in pH upon addition of a large amount of a strong acid or base.
a solution that doesn't resist significant changes in pH upon addition of a small amount of a strong acid or base.
a solution that resists significant changes in pH upon addition of a small amount of a strong acid or base.
none of the above
Which is the weakest acid?
HF
HNO2
CH3COOH
HClO
Which Ka would be best to prepare a buffer with pH of 9.5
Ka = 1.9 x 10-5
Ka = 9.5 x 10-4
Ka = 1.2 x 10-10
Ka = 2.0 x 10-9
30mL of 0.1M weak acid (Ka = 1.0x10-5) is titrated with .2M strong base.
At the half equivalence point, the pH is closest to:
1
3
5
7
9
What is the best indicator for a weak base titrated with a strong acid
Congo Red (pH change 4 to 5)
Bromothymol Blue (pH change 6.5 to 7.5)
Phenolthalein (pH change 8 to 9)
Alizarin Yellow (pH change 11 to 12)
Zn(OH)2 + HNO3 ---> H2O + Zn(NO3)2
When equal moles of HCl and NaOH are mixed which results in greatest concentration?
Cl-1
H+1
OH-1
NH3+1
To neutralize 0.20 moles of Ba(OH)2, how many moles of HCl are needed?
0.40
0.20
0.60
0.100
At which point in the titration of the weak acid HA was [A-] the greatest?
U
R
T
Q
APMCQ: A solution is prepared by adding 100 mL of 1.0 M HC2H3O2(aq) to 100 mL of 1.0 M NaC2H3O2(aq). The solution is stirred and its pH is measured to be 4.73. After 3 drops of 1.0 M HCl are added to the solution, the pH of the solution is measured and is still 4.73. Which of the following equations represents the chemical reaction that accounts for the fact that acid was added but there was no detectable change in pH?
H3O+(aq) + OH-(aq) → 2 H2O(l)
H3O+(aq) + Cl-(aq) → HCl(g) + H2O(l)
H3O+(aq) + C2H3O2-(aq) → HC2H3O2(aq) +H2O(l)
H3O+(aq) + HC2H3O2(aq) → H2C2H3O2+(aq) + H2O(l)
APMCQ: A solution is prepared by mixing 50 mL of 1 M NaH2PO4 with 50 mL of 1 M Na2HPO4. On the basis of the information above, which of the following species is present in the solution at the lowest concentration?
Na+
HPO42-)
H2PO4-
PO43−
APMCQ: A solution of a weak monoprotic acid is titrated with a solution of a strong base, KOH. Consider the points labeled (A) through (E) on the titration curve
that results, as shown above.
The point at which the concentrations of the weak acid and its conjugate base are approximately equal
A
B
C
D
E
APMCQ: An unknown acid is dissolved in 25 mL of water and titrated with 0.100 M NaOH. The results are shown in the titration curve above. Which of the following could be the unknown acid?
Fluoroacetic acid, pKa = 2.6
Glycolic acid, pKa = 3.8
Propanoic acid, pKa = 4.9
Hypochlorous acid, pKa = 7.5
Boric acid, pKa = 9.3
APMCQ: At 25°C, aqueous solutions with a pH of 8 have a hydroxide ion concentration, [OH-], of
1 x 10-14 M
1 x 10-8 M
1 x 10-6 M
1 M
8 M
APMCQ: The pH of solutions of four acids prepared at various concentrations were measured and recorded in the table above.
The four acids are, in no particular order, chlorous, hydrochloric, lactic, and propanoic.
For which acid is the value of the acid-dissociation constant, Ka , the smallest?
Acid 1
Acid 2
Acid 3
Acid 4
APMCQ: A student mixes 40. mL of 0.10 M HBr(aq) with 60.mL of 0.10 M KOH (aq) at 25°C. What is the [OH−] of the resulting solution?
[OH−]=0.060 M
[OH−]=0.033 M
[OH−]=0.020 M
[OH−]= 1 x 10 -7 M
