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WorksheetsAcids and Bases (AP Chem)
Total questions: 15
Worksheet time: 35mins
A buffer solution is prepared by mixing equal volumes of 0.50 M weak acid with 1.0 M of its conjugate base. Based on the data given in the table above, which of the following pairs of chemical solutions should be used to prepare the buffer solution so that the pH will be between 4 and 7?
CH3COOH and NH3
CH3COOH and CH3COONa
H2CO3 and NH3
H2CO3 and Na2CO3
Ascorbic acid, H2C6H6O6(s), is a diprotic acid with K1 = 7.9 × 10–5 and K2 = 1.6 × 10–12. In a 0.005 M aqueous solution of ascorbic acid, which of the following species is present in the lowest concentration?
H3O+(aq)
H2C6H6O6(aq)
HC6H6O6-(aq)
C6H6O62-(aq)
In the titration of a weak acid of unknown concentration with a standard solution of a strong base, a pH meter was used to follow the progress of the titration. Which of the following is true for this experiment?
The [H+] at the equivalence point equals the ionization constant of the acid.
The pH at the equivalence point depends on the indicator used.
The graph of pH versus volume of base added rises gradually at first and then much more rapidly.
The graph of pH versus volume of base added shows no sharp rise.
Which of the following is the correct equilibrium expression for the hydrolysis of CO3 2– ?
Which of the following best approximates the Ka value for this weak acid?
1 x 10–3
1 x 10–4
1 x 10–5
1 x 10–6
Which point on the titration curve corresponds to the point at which the moles of the added strong base are equal to the moles of the weak acid initially present?
Q
R
S
T
At point P in the titration, which of the following species has the highest concentration?
HA
A–
H3O+
OH–
Which of the following best represents a 0.100-molar solution of H2SO4 in water?
Equal moles of the indicated acids are dissolved in the amounts of water shown in the beakers below. In which solution will the percent ionization of the acid be the lowest?
Beaker 1
Beaker 2
Beaker 3
Beaker 4
Mixtures that would be considered buffers include which of the following?
0.10 M HCl + 0.10 M NaCl
0.10 M HF + 0.10 M NaF
0.10 M HBr + 0.10 M NaBr
0.10 M HI + 0.10 M NaI
HSO4¯ + H2O ↔ H3O+ + SO4 2¯ In the equilibrium represented above, the species that act as bases include which of the following?
HSO4-
H2O
SO4 2¯
H2O and SO4 2¯
Equal volumes of 0.10-molar H3PO4 and 0.20-molar KOH are mixed. After equilibrium is established, the type of ion in solution in largest concentration, other than the K+ ion, is
H2PO4 –
HPO4 2–
PO4 3–
OH-
Which of the following aqueous solutions containing 1:1 mole ratios of the following pairs of substances at 1 M concentrations will have the lowest pH?
NH3 and NH4Cl
H3PO4 and NaH2PO4
HCl and NaCl
NaOH and NH3
What part of the curve corresponds to the optimum buffer action for the acetic acid/acetate ion pair?
Point V
Point Z
Along all of section WY
Along all of section YZ
Which of the following indicators is the best choice for this titration?
Methyl orange (pH range of color change is 3.2 - 4.4)
Methyl red (pH range of color change is 4.8 - 6.0)
Bromothymol blue (pH range of color change is 6.1 - 7.6)
Phenolphthalein (pH range of color change is 8.2 - 10.0)
