DATA TABLE:
A. Titration Data for Actual Concentration
Flask Volume of
Volume of Titrant
Actual Concentration of Acetic
No.
Acetic Acid
(NaOH)
Concentration of NaOH Acid
1
5
1.8
0.2
0.072
2
5
4
0.2
0.160
3
5
5.9
0.2
0.236
4
5
10.2
0.2
0.408
5
5
14.3
0.2
0.572
B. Titration Data for Final Concentration
Trial 1
Flask
No.
Volume of Acetic Acid Volume of Titrant (NaOH)
1
5
1.7
2
5
3.4
3
5
4.9
4
5
9
5
5
11.7
Trial 2
Flask
No.
Volume of Acetic Acid Volume of Titrant (NaOH)
1
5
1.8
2
5
3
3
5
5.8
4
5
11.1
5
5
12.5
Concentration
Final Concentration of
of NaOH
Acetic Acid
0.2
0.068
0.2
0.136
0.2
0.196
0.2
0.36
0.2
0.468
Concentration
Final Concentration of
of NaOH
Acetic Acid
0.2
0.072
0.2
0.12
0.2
0.232
0.2
0.444
0.2
0.5
B1. Statistical Analysis for Final Concentration
Final Concentration
Trial 2
0.072
0.12
0.232
0.444
0.5
Trial 1
0.068
0.136
0.196
0.36
0.468
Average
0.070
0.128
0.214
0.402
0.484
C. Adsoprtion Data of Acetic
Flask No.
1
2
3
4
5
Ca
0.072
0.160
0.236
0.408
0.572
Cf
0.070
0.128
0.214
0.402
0.484
Ca-Cf=Cad
0.002
0.032
0.022
0.006
0.088
mi
0.0001
0.0018
0.0012
0.0003
0.0048
1/Cad
500.000
31.250
45.455
166.667
11.364
1/mi
10000
555.556
833.333
3333.333
208.333
%=Cad/Ca * 100
2.778
20.000
9.322
1.471
15.385
D. Data for Titration Curve of Acetic Acid
Solution Concentration
Absorbance
1
0.07
2
0.128
3
0.214
4
0.402
5
0.484
0.182
0.144
0.181
0.155
0.187
E. Data for Calibration Curve of Glacial Acetic Acid
Solution Concentration
1
2
3
4
5
6
Absorbance
0.01
0.04
0.08
0.1
0.4
0.8
0.128
0.171
0.166
0.172
0.176
0.175
Sample Calculation:
A. For Actual and Final Concentration
𝑀1𝑉1 = 𝑀2𝑉2
𝑀1𝑉1
𝑀2 =
𝑉2
M1 = 0.02 NaOH
V1 = Volume of Titrant = 1.8 mL
V2 = Volume of Acetic Acid = 5 mL
𝐴𝑐𝑡𝑎𝑢𝑙 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 = 𝑀2 =
(0.02 𝑀)(1.8 𝑚𝐿)
= 0.072
(5 𝑚𝐿)
Trial 1:
M1 = 0.02 NaOH
V1 = Volume of Titrant = 1.7 mL
V2 = Volume of Acetic Acid = 5 mL
𝐹𝑖𝑛𝑎𝑙 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 = 𝑀2 =
(0.02 𝑀)(1.7 𝑚𝐿)
= 0.068
(5 𝑚𝐿)
Trial 2:
M1 = 0.02 NaOH
V1 = Volume of Titrant = 1.8 mL
V2 = Volume of Acetic Acid = 5 mL
𝐹𝑖𝑛𝑎𝑙 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 = 𝑀2 =
𝐴𝑣𝑒𝑟𝑎𝑔𝑒 𝐹𝑖𝑛𝑎𝑙 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 =
(0.02 𝑀)(1.8 𝑚𝐿)
= 0.072
(5 𝑚𝐿)
𝑇𝑟𝑖𝑎𝑙 1 + 𝑇𝑟𝑖𝑎𝑙 2 0.068 + 0,072
=
= 0.070
2
2
B. Calculation for Adsorption of Aceetic Acid
B1. Cad
𝐶𝑎𝑑 = 𝐶𝑎 − 𝐶𝑓 = 0.072 − 0.070 = 0.002
B2. mi
𝑚𝑖 =
(0.072 − 0.070) 𝑥 55
= 0.0001
1.0017 𝑥 1000
B3. 1/Cad
1
1
=
= 500
𝐶𝑎𝑑 0.002
B4. 1/mi
1
1
=
= 1000
𝑚𝑖 0.0001
B4.Percent
%=
𝐶𝑎𝑑
0.002
𝑥 100 =
𝑥 10 = 2.778 %
𝐶𝑎
0.072
Discussion:
A. Adsorption of Acetic Acid
The adsorption of acetic acid onto a surface is studied by analyzing the difference between the initial concentration
(Ca) and the final concentration (Cf) after the interaction, represented as the adsorbed concentration (Cad=Ca−Cf
). The data shows that higher initial concentrations generally lead to greater absolute adsorption values, as seen
in flask 5, where Ca was 0.572 mol/L and Cad reached 0.088 mol/L. However, the efficiency of adsorption,
expressed as the percentage of Cad/Ca×100 , does not always increase with higher initial concentrations. For
example, flask 2 with an initial concentration of 0.160 mol/L achieved an adsorption efficiency of 20%, while flask
5 had a lower efficiency of 15.385% despite a higher Cad. This suggests that as the concentration increases, the
adsorption sites on the surface become saturated, leading to a decline in relative efficiency.
The data also show other trends. At low initial concentrations, the adsorption efficiency is higher, suggesting that
adsorption sites on the surface are readily available. For example, flask 1, with an initial concentration of 0.072
mol/L, had a high adsorption efficiency of 2.778%. In contrast, as the concentration increases, the percentage of
adsorption decreases because fewer sites remain available for adsorption. At high concentrations, the adsorption
stops increasing significantly because the surface becomes full, and there are no more free sites for the acetic acid
to bind. This leveling off of adsorption is called a plateau and is a common characteristic of systems with a limited
number of adsorption sites.
1/mi vs 1/Cad
10000,000
9000,000
8000,000
7000,000
1/mi
6000,000
5000,000
4000,000
3000,000
y = 18,212x + 2,4739
R² = 1
2000,000
1000,000
0,000
0,000 100,000200,000300,000400,000500,000600,000
1/Cad
The graph plotting 1/Cad (reciprocal of the adsorbed concentration) against 1/mi (reciprocal of the mass of
adsorbent per unit volume) provides key insights into the adsorption behavior of acetic acid. This graph is typically
used to analyze adsorption using models like the Langmuir isotherm, which assumes that adsorption occurs on a
uniform surface with a finite number of identical sites.
From the graph, the linear relationship suggests that the adsorption process follows a predictable pattern. A
straight line indicates that the adsorption behavior aligns with the Langmuir model, where the adsorbent surface
becomes progressively saturated as more acetic acid molecules are adsorbed. The slope and intercept of the graph
are important because they can be used to calculate constants related to the adsorption capacity and strength of
interaction between the acetic acid molecules and the adsorbing surface.
The shape of the graph also highlights an important aspect of adsorption: at low concentrations of acetic acid, the
adsorption sites on the surface are readily available, so a small increase in concentration leads to a significant
increase in adsorption. However, as the concentration increases, the surface becomes saturated, and fewer sites
are available. This is why the reciprocal values (1/Cad and 1/mi) increase more slowly at higher concentrations,
creating the straight-line trend in the graph. This demonstrates that the adsorption of acetic acid is influenced by
both the availability of adsorption sites and the concentration of the solution, with surface saturation ultimately
limiting the system's efficiency at higher concentrations.
B. Titration Curve of Acetic Acid
Titration Curve of Acetic Acid
0,2
0,18
0,16
Absorbance
0,14
0,12
y = 0,0184x + 0,165
R² = 0,0295
0,1
0,08
0,06
0,04
0,02
0
0
0,1
0,2
0,3
0,4
0,5
0,6
Concentration
The titration curve of acetic acid, as shown in the graph, is not linear and does not increase continuously, reflects
the characteristic behavior of a weak acid during titration. This non-linear behavior reflects the dynamic
equilibrium between acetic acid and its conjugate base during the titration process. Initially, the graph shows an
increase in absorbance with the addition of titrant, reflecting the initial reaction between acetic acid and sodium
hydroxide (NaOH). This is followed by a decrease in absorbance, which can be attributed to the stabilization of the
reaction as the system begins to buffer the changes in pH.
As the titration progresses, the absorbance increases again, corresponding to the phase where the buffering
capacity of acetic acid is being overcome, and the equilibrium is shifting more significantly toward the formation
of acetate ions. Shortly after this phase, another decrease is observed, which may indicate a temporary
stabilization or saturation effect in the reaction dynamics. Finally, as the titration approaches completion and the
equivalence point, the absorbance increases once more, signifying the completion of the neutralization reaction
and the dominance of acetate ions in the solution.
This alternating pattern of increases and decreases in absorbance highlights the unique behavior of weak acids
like acetic acid during titration. The changes are a result of the complex interaction between the partial dissociation
of acetic acid, the buffering action that resists sudden shifts in pH, and the gradual neutralization as sodium
hydroxide is added. Unlike strong acids, which fully ionize and show a more linear titration curve, weak acids exhibit
this fluctuating behavior because their ionization and equilibrium states shift continuously throughout the titration
process. This distinctive pattern underscores the importance of equilibrium and buffering effects in understanding
weak acid titration curves.
C. Calibration Curve of Glacial Acetic
Calibration Curve of Glacial Acetic Acid
0,2
0,18
0,16
Absorbance
0,14
y = 0,0283x + 0,1579
R² = 0,2288
0,12
0,1
0,08
0,06
0,04
0,02
0
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
Concentration
The calibration curve graph of glacial acetic acid, as presented in the graph, provides a visual representation of the
relationship between the concentration of acetic acid and its corresponding absorbance values. The graph shows
a generally linear trend, with absorbance values increasing as the concentration increases. However, slight
deviations from perfect linearity can be observed, particularly at higher concentrations, suggesting potential
limitations in the measurement system or saturation effects in the spectrophotometer.
The linearity of the calibration curve is crucial because it establishes a reliable relationship between concentration
and absorbance, allowing for the determination of unknown concentrations through interpolation. The equation
of the line, y=0.0283x+0.1579, where y represents absorbance and x represents concentration, supports this
relationship. The R2R^2R2 value of 0.2288 indicates that while there is a correlation, some variability exists,
possibly due to experimental inconsistencies or instrument sensitivity.
This graph is essential for the experiment as it serves as a reference for comparing the absorbance values obtained
during titration. Any deviations in absorbance readings during the titration process can be cross-checked against
the calibration curve to ensure the accuracy and reliability of the data. Overall, the calibration curve is a
foundational tool in the analysis of glacial acetic acid, enabling accurate quantification and supporting the validity
of the findings in the activity.
Summary and Conclusion:
The graphs for adsorption, titration, and calibration of acetic acid collectively reveal important aspects of its behavior and
properties. The adsorption data shows that while higher initial concentrations lead to greater adsorbed amounts
(CadC_{ad}), the efficiency decreases at higher concentrations due to the saturation of adsorption sites, following the
Langmuir isotherm as indicated by the linear 1/Cad1/C_{ad} vs. 1/mi1/m_i graph. The titration curve reflects the dynamic
equilibrium of acetic acid as a weak acid, with alternating increases and decreases in absorbance due to buffering and the
gradual neutralization process, highlighting its distinct behavior compared to strong acids. The calibration curve provides
a largely linear relationship between absorbance and concentration, allowing for accurate determination of unknown
concentrations, despite slight deviations at higher concentrations caused by instrumental limitations. Together, these
findings underscore the interplay between adsorption, equilibrium, and quantification in understanding acetic acid’s
chemical behavior.
References:

Libretexts. (2022, August 9). 21.19: Titration curves. Chemistry LibreTexts.
https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK12)/21%253A_Acids_and_Bases/21.19%253A_Titration_Curves

Hasdemir, İ. M., Yılmazoğlu, E., Güngör, S., & Hasdemir, B. (2022). Adsorption of acetic acid
onto activated carbons produced from hazelnut shell, orange peel, and melon seeds. Applied
Water Science, 12(12). https://doi.org/10.1007/s13201-022-01797-y

Tube, T. (2023, July 22). Adsorption of acetic acid on charcoal and the isotherm - Tuition Tube.
Tuition Tube. https://tuitiontube.com/adsorption-of-acetic-acid-on-charcoal-validity-offreundlichs-adsorption-isotherm-langmuirs-adsorption-isotherm/

Filer, D. (2014, December 9). Adsorption of Acetic Acid on Activated Charcoal .
https://daniellefiler.weebly.com/uploads/5/5/2/8/55282799/pchem_lab_4_aa.pdf

Libretexts. (2024, August 30). 2.5: Uncertainty in values determined from a Calibration Curve.
Chemistry LibreTexts.
https://chem.libretexts.org/Courses/Duke_University/CHEM_401L%3A_Analytical_Chemistry_
Lab/CHEM_401L%3A_Analytical_Chemistry_Lab_Manual/02%3A_Quantitative_Techniques_
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