1. A student is conducting a titration to equivalence between a
weak base and a strong acid. Which of the indicators should the
student select to help determine equivalence?
a. methyl red, pKa = 5.0
b. thymol blue, pKa = 2.0
c. bromothymol blue, pKa = 7.0
d. phenolphthalein, pKa = 9.3
2. A student dilutes a strong acid by adding 100 mL of water to 100
mL of the solution. Which of the following is true about the
diluted solution?
a. The pH of the solution will increase by less than 1.
b. The pH of the solution will increase by 1.
c. The pH of the solution will remain the same.
d. The pH of the solution will decrease by less than 1.
3. Which of the following is the correct net ionic reaction of
the weak acid CH3CH2COOH reacting with the strong base NaOH?
a. CH3CH2COOH (aq) + OH- (aq) --> CH3CH2COO- (aq) + H2O (l)
b. CH3CH2COOH (aq) + NaOH (aq) --> NaCH3CH2COO (aq) + H2O (l)
c. H+ (aq) + OH- (aq) --> H2O (l)
d. CH3CH2COOH (aq) --> CH3CH2COO- (aq) + H+ (aq)
4. A buffer is created with equimolar concentrations of weak acid
and a salt containing the conjugate base of the weak acid. Which of
the following is true when a small amount of HCl is added to the
buffer?
a. The pH of the buffer will decrease slightly as the
strong acid reacts with the conjugate base forming more weak
acid.
b. The pH of the buffer will increase slightly as the
strong acid reacts with the weak acid forming more conjugate
base.
c. The pH of the buffer will increase rapidly as the
strong acid reacts with the conjugate base forming more weak
acid.
d. The pH of the buffer will decrease rapidly as the
strong acid reacts with the weak acid forming a more conjugate
base.
5. As the temperature of the water is increased above 25°C, the pH
decreases. Which of the statements below about water is true?
a. As the temperature of water increases, the pOH also
decreases.
b. The pOH of water is greater than 7 at temperatures
greater than 25°C.
c. The [H+] is greater than the [OH-] for water at
temperatures greater than 25°C.
d. The Kw of water decreases as the temperature
increases above 25°C.
6. A solution is created by mixing 50 mL of 1 M HA (aq), Ka =
1.0 x 10^-4, with 25 mL of 1 M NaOH (aq). Which of the following gives
the correct relationship of the concentration of the ions in
solution?
a. pH > pKa and [HA] < [A-]
b. pH = pKa and [HA] = [A-]
c. pH < pKa and [HA] > [A-]
d. pH < pKa and [HA] < [A-]
7. Each of the systems below has a total volume of 100 mL. Which of
the systems would be able to absorb the most acid without a
significant change in pH?
a. 2.0 M CH3CH2COOH and 2.0 M NACH3CH2COO
b. 3.0 M HCl and 3.0 M NaOH
c. 2.0 M HC2H3O2 and 0.15 M NaC2H3O2
d. 1.0 M NH3 and 1.0 M NH4CI
8. Consider the acid HXOy where X is a halogen that is less
electronegative than oxygen. Which of the following gives the
relationship between Ka of the acid and the value of y and gives
the correct reasoning?
a. As y increases, the value of Ka decreases because
the conjugate base of the acid becomes less stable.
b. As y increases, the value of Ka increases because
the conjugate base of the acid becomes less stable.
c. As y increases, the value of Ka decreases because
the conjugate base of the acid becomes more stable.
d. As y increases, the value of Ka increases because
the conjugate base of the acid becomes more stable.
9. A 0.10 M sample of a weak acid has a Ka of 4.0 x 10^-5. What
is the pH of the weak acid?
a. between 2-3
b. between 1-2
c. between 3-4
d. between 11-12