Abia State Polytechnic Chemistry Acid Base Titrations Lab

Answer Questions:Experiment: Acid-Base Titrations
7 Question Need to be Answer
1- Phenolphthalein changes from clear to pink at a pH value of about 9.
According to your results, with which combination(s) of strong or weak acids
and bases can phenolphthalein be used to determine the equivalence point? Do
your results make sense? If not, explain what you should have observed and
why?
2- Methyl red is an acid-base indicator that changes color at a pH value of about
5. From what you learned in this lab, methyl red could be used to
determine the equivalence point of what combination(s) of strong or weak acids
and bases (strong acid/strong base, strong acid/weak base, strong base/weak
acid)? Do your results make sense? If not, explain what you should have
observed and why?
3- You’re given a list of weak acids and their Kavalues, an unknown weak acid
from the list that you will titrate with NaOH and a pH meter. How could you
determine the identity of your unknown weak acid? (5 pts)
5- Write Data & Results for each tables and graphs (Tables
are appropriately labeled (each correctly identified, appropriate title, and units are
included. Required figures are also included.)( you have to write under each table,
provide a one- sentence description of what the table is showing the reader).
6-
write Analysis (Includes a separately labeled section with an
explanation of results, trends, and what they mean.)
7- Find the Equivalence point Volume and Equivalence Point pH for 3 tables.
Acid Base Titrations
Part 1: HCl + NaOH
Enter the pH and volume of NaOH added. Include the initial pH of the HCl solution with 0 mL of NaOH
added.
Solution pH
2.76
3
3.25
3.35
3.45
3.65
3.85
9.71
10.5
11.6
11.8
11.9
14
12
Solution pH
Vol NaOH (mL)
0
4
5
5.5
6
6.2
6.5
7
8
10
12
13
10
8
6
4
2
0
0
5
10
Vol NaOH Added (mL)
15
Acid Base Titrations
Part 2: Acetic Acid + NaOH
Enter the pH and volume of NaOH added. Include the initial pH of the acetic acid solution with 0 mL of
NaOH added.
Solution pH
3.81
4.5
5
5.75
6.6
10.41
11.06
11.39
11.58
14
12
Solution pH
Vol NaOH (mL)
0
1
2,5
4
5
5.5
6
7
8
10
8
6
4
2
0
0
2
4
6
Vol NaOH Added (mL)
8
10
Acid Base Titrations
Part 3: HCl + NH3
Enter the pH and volume of ammonia added. Include the initial pH of the HCl solution with 0 mL of
ammonia added.
0
2
5
7
9
10.5
11
12.3
13
13.5
14
15
16
17
19
19.5
20.5
22
24
25
26
27
29
Solution pH
2.79
2.85
2.97
3.1
3.3
3.57
3.67
4.88
5.5
6.2
7.05
7.5
8.56
8.7
8.9
8.98
9.03
9.15
9.21
9.25
9.27
9.3
9.36
10
8
Solution pH
Vol NH3 (mL)
6
4
2
0
0
10
20
30
Vol Ammonia Added (mL)
40