370
Acid-Base Equilibria
28. A 20.0 ml sample of 1.00 M HNO 2 is added to 50.0 ml of 0.600 M NaNO 2 . What
is the pH of the solution?
29. A 25.0 g sample of NH 4 C1 is added to 200 ml of 0.500 M NH 3 . What is the pH
of the solution?
30. How many grams of NH 4 NO 3 must be added to 100 ml of 3.00 M NH 3 in order
that the solution shall have a pH of 8.50?
31. A 75.0 ml sample of 2.00 M NH 4 NO 3 is added to 100 ml of 1.00 M NH 3 . What is
the pH of the resulting solution?
32. What is the pH of the solution that results from the addition of 25.0 ml of
0.200 M KOH to 50.0 ml of 0.150 M HNO 2 ?
33. What is the pH of the solution that results from the addition of 25.0 ml of
0.200 M NH 3 to 30.0 ml of 0.150 M HC1?
34. The pH of each of the following solutions is determined by pH meter or color
comparison. Calculate the hydrolysis constant for each salt.
(a) 0.100 M NH 4 C1 has a pH of 5.12
(b) 0.0100 M LiCHO 2 has a pH of 7.89
(c) 0.100 M NaC 2 H 3 O 2 has a pH of 8.88
(d) 0.0100 M (CH 3 ) 2 NH 2 C1 has a pH of 6.38
(e) 0.100 M NaCN has a pH of 11.10
35. Calculate the pH of each of the following solutions.
(a) 0.100 M NaCNO
(e) 0.800 M C 2 H 5 NH 3 C1
(b) 0.0500 M NH 4 NO 3
(f) 0.0100 M KC1
(c) 1.50 M KNO 2
(g) 1.50 M KC 2 H 3 O 2
(d) 0.350 M NaNO 3
(h) 1.00 x 10~
9 M NaOH
36. Calculate the pH of the solution resulting from each of the following titration
processes.
(a) 25.0 ml of 0.200 M HNO 3 + 25.0 ml of 0.200 M KOH
(b) 40.0 ml of 0.100 M HCHO 2 + 20.0 ml of 0.200 M NaOH
(c) 35.0 ml of 0.100 M HNO 3 + 35.0 ml of 0.100 M C 5 H 5 N
(d) 20.0 ml of 0.250 M H 3 BO 3 + 10.0 ml of 0.500 M KOH
37. Select a suitable endpoint indicator for each of the titrations listed in Problem
36.
38. If 10.0 ml of 1.00 M HNO 2 are added to 20.0 ml of 2.00 M NaNO 2 , what will be
the pH of the resulting solution?
39. How would you prepare a solution, using HC 2 H 3 O 2 and NaC 2 H 3 O 2 , so that the
pH of the resulting solution is 5.5?
40. You have a buffer solution that contains 1.00 mole of NaC 2 H 3 O 2 and 1.00 mole
of HC 2 H 3 O 2 per liter.
(a) Calculate the pH of this solution.
(b) Calculate the pH of the solution after the addition of 0.10 mole of solid
NaOH to a liter.
Acid-Base Equilibria
28. A 20.0 ml sample of 1.00 M HNO 2 is added to 50.0 ml of 0.600 M NaNO 2 . What
is the pH of the solution?
29. A 25.0 g sample of NH 4 C1 is added to 200 ml of 0.500 M NH 3 . What is the pH
of the solution?
30. How many grams of NH 4 NO 3 must be added to 100 ml of 3.00 M NH 3 in order
that the solution shall have a pH of 8.50?
31. A 75.0 ml sample of 2.00 M NH 4 NO 3 is added to 100 ml of 1.00 M NH 3 . What is
the pH of the resulting solution?
32. What is the pH of the solution that results from the addition of 25.0 ml of
0.200 M KOH to 50.0 ml of 0.150 M HNO 2 ?
33. What is the pH of the solution that results from the addition of 25.0 ml of
0.200 M NH 3 to 30.0 ml of 0.150 M HC1?
34. The pH of each of the following solutions is determined by pH meter or color
comparison. Calculate the hydrolysis constant for each salt.
(a) 0.100 M NH 4 C1 has a pH of 5.12
(b) 0.0100 M LiCHO 2 has a pH of 7.89
(c) 0.100 M NaC 2 H 3 O 2 has a pH of 8.88
(d) 0.0100 M (CH 3 ) 2 NH 2 C1 has a pH of 6.38
(e) 0.100 M NaCN has a pH of 11.10
35. Calculate the pH of each of the following solutions.
(a) 0.100 M NaCNO
(e) 0.800 M C 2 H 5 NH 3 C1
(b) 0.0500 M NH 4 NO 3
(f) 0.0100 M KC1
(c) 1.50 M KNO 2
(g) 1.50 M KC 2 H 3 O 2
(d) 0.350 M NaNO 3
(h) 1.00 x 10~
9 M NaOH
36. Calculate the pH of the solution resulting from each of the following titration
processes.
(a) 25.0 ml of 0.200 M HNO 3 + 25.0 ml of 0.200 M KOH
(b) 40.0 ml of 0.100 M HCHO 2 + 20.0 ml of 0.200 M NaOH
(c) 35.0 ml of 0.100 M HNO 3 + 35.0 ml of 0.100 M C 5 H 5 N
(d) 20.0 ml of 0.250 M H 3 BO 3 + 10.0 ml of 0.500 M KOH
37. Select a suitable endpoint indicator for each of the titrations listed in Problem
36.
38. If 10.0 ml of 1.00 M HNO 2 are added to 20.0 ml of 2.00 M NaNO 2 , what will be
the pH of the resulting solution?
39. How would you prepare a solution, using HC 2 H 3 O 2 and NaC 2 H 3 O 2 , so that the
pH of the resulting solution is 5.5?
40. You have a buffer solution that contains 1.00 mole of NaC 2 H 3 O 2 and 1.00 mole
of HC 2 H 3 O 2 per liter.
(a) Calculate the pH of this solution.
(b) Calculate the pH of the solution after the addition of 0.10 mole of solid
NaOH to a liter.