Name: 
 

Acid-Base Equilibrium



Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

 1. 

In the following reaction

HCO3-(aq) + H2O(l) <=> CO32-(aq) + H3O+(aq)
a.
HCO3- is an acid and H2O is its conjugate base.
b.
HCO3- is an acid and CO32- is its conjugate base.
c.
H3O+ is an acid and HCO3- is its conjugate base.
d.
H2O is an acid and CO32- is its conjugate base.
e.
H3O+ is an acid and CO32- is its conjugate base.
 

 2. 

The conjugate acid of HSO4- is ____.
a.
OH-
b.
SO42-
c.
H2SO4
d.
H2O
e.
H3O+
 

 3. 

Which is NOT an amphiprotic species in water?
a.
HC2O4-
b.
CH3CO2-
c.
HPO42-
d.
H2PO4-
e.
HCO3-
 

 4. 

At 15 °C, the water ionization constant, Kw, is 4.5 x 10-15. What is the H3O+ concentration in neutral water at this temperature?
a.
2.0 x 10-29 M
b.
4.5 x 10-15 M
c.
6.7 x 10-8 M
d.
1.5 x 10-7 M
e.
2.2 M
 

 5. 

A solution is prepared by diluting 0.16 mol HNO3 with water to a volume of 1.5 L. What is the pH of this solution?
a.
-0.80
b.
0.80
c.
0.97
d.
1.83
e.
2.24
 

 6. 

At 25 °C, what is the H3O+ concentration in 0.044 M NaOH(aq)? (Kw = 1.0 x 10-14)
a.
4.4 x 10-16 M
b.
2.3 x 10-13 M
c.
4.4 x 10-7 M
d.
1.36 M
e.
12.6 M
 

 7. 

Which one of the following aqueous solutions will have a pH of 10.00 at 25 °C? (Kw = 1.0 x 10-14)
a.
1.0 x 101 M HCl
b.
1.0 x 102 M HNO3
c.
1.0 x 10-4 M HBr
d.
1.0 x 10-4 M NaOH
e.
1.0 x 102 M KOH
 

 8. 

What is the H3O+ concentration of an aqueous solution with a pH of 12.17?
a.
6.8 x 10-13 M
b.
1.9 x 10-9 M
c.
5.2 x 10-6 M
d.
1.5 x 10-2 M
e.
1.1 M
 

 9. 

What is the OH- concentration of an aqueous solution with a pH of 11.45? (Kw = 1.0 x 10-14)
a.
3.5 x 10-12 M
b.
9.4 x 10-10 M
c.
1.1 x 10-5 M
d.
2.8 x 10-3 M
e.
7.8 x 10-2 M
 

 10. 

An aqueous solution with a pH of 3.00 is diluted from 2.0 L to 4.0 L. What is the pH of the diluted solution?
a.
1.50
b.
1.73
c.
3.00
d.
3.30
e.
6.00
 

 11. 

Benzoic acid has a pKa value of 9.14. What is the value of Kb for sodium benzoate?
a.
7.2 x 10-10
b.
1.4 x 10-5
c.
1.1 x 10-4
d.
-4.86
e.
4.86
 

 12. 

In the following reaction:
NH4+  (aq) + H2O (aq) <=> NH3 (aq) + H3O+ (aq)
a.
NH4+ is an acid and H2O is its conjugate base
b.
H2O is a base and NH3 is its conjugate acid 
c.
NH4+ is an acid and H3O+ is its conjugate base
d.
H2O is a base and H3O+ is its conjugate acid
e.
NH4+ is a base and H2O is its conjugate acid 
 

 13. 

A 0.10 M solution of an electrolyte has a pH of 4.5. The electrolyte is
a.
a strong acid
b.
a strong base.
c.
a weak acid.
d.
a weak base. 
e.
none of the above
 

 14. 

Acetic acid, HC2H3O2 is a weak monoprotic acid.  What is the  concentration of H+ in 2.0 M acetic acid?
a.
1.0 M
b.
2.0 M
c.
>2.0 M
d.
<2.0 M
e.
none of the above
 

 15. 

What is the  concentration of H3O+ in a neutral solution?
a.
0.0 M
b.
1.0 x 10-7 M
c.
1.0 x 10-14 M
d.
>1.0 x 10-14 M
e.
< 1.0 x 10-7 M
 

 16. 

What is the concentration of the hydroxide ions in an acidic solution?
a.
0.0 M
b.
1.0 x 10-7 M
c.
1.0 x 10-14 M
d.
>1.0 x 10-7 M
e.
< 1.0 x 10-7 M
 

 17. 

What is the concentration of the hydronium ions in an acidic solution?
a.
0.0 M
b.
1.0 x 10-7 M
c.
1.0 x 10-14 M
d.
>1.0 x 10-7 M
e.
< 1.0 x 10-7 M
 

 18. 

What is the concentration of the hydroxide ion given that the concentration of the hydronium ion is 1.5 x 10-5 M?
a.
6.7 x 10-10 M
b.
1.5 x 109 M
c.
1.0 x 10-14 M
d.
1.0 x 10-19 M
e.
None of the above
 

 19. 

What is the concentration of hydronium ions in a solution given that the concentration of hydroxide ions is 2.31 x 10-4 M
a.
4.33 x 10-11 M
b.
2.31 x 1010 M
c.
2.31 x 10-18 M
d.
1.01 x 10-5 M
e.
None of the above
 

 20. 

A buffer solution is all of the following EXCEPT:
a.
a solution that resists a change in pH when a base is added.
b.
a solution that resists a change in pH when an acid is added.
c.
a solution that contains both a weak acid and its conjugate base.
d.
a solution that regulates pH by the addition of a strong acid or base.
e.
All of the above are true
 



 
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