Lab Report PHD 114
Lab Report PHD 114
Lab Report PHD 114
LABORATORY REPORT
NAME
MATRIX NO
2016469964
LECTURER
PUAN
AINNIE
ABDULLAH
PARTNER
EXP. NUMBER
GROUP
PH110C2
TITLE
DATE
RAHAYU
BINTI
EXPERIMENT 1
DETERMINATION OF THE MOLARITY AND CONCENTRATION
POTASSIUM PERMANGANATE (VII) SOLUTION, KMnO4
Purpose
The purpose of the lab is to find the molarity and the concentration
of potassium permanganate (VII) solution, KMnO4
Apparatus
Burette, pipette, filter funnel, beaker, conical flask, retort stand with
clamp.
Chemicals
Procedure
(II)
Data
OF
Burette reading
Experiment
Final reading
(cm3)
22.60
20.40
42.00
Initial reading
(cm3)
0.00
0.00
21.50
Volume of KmnO4
used (cm3)
22.60
20.40
20.50
20.00
20.00
20.00
20.40 20.50
20.45cm3
2
Calculation
The molarity of KMnO4 solution:
MA(20.45)
1
0.1(20.00)
5
MA 0.0196M
Discussion of Theory
In this experiment, we need to determine the molarity and concentration of potassium
permanganate (VII) solution, KMnO4.
The reaction between potassium permanganate (VII) solution and iron (II) ammonium
sulphate involves a redox reaction, which is occurs in acidic medium as we add a 1
test-tube full of sulphuric acid in it. The balanced half-ionic equation for the reactions
can be represented as:
(i)
Fe2+ Fe3+ + e-
(ii)
Potassium permanganate (VII) solution serves as its own indicator, thats why we
dont have to add any indicator such as Methyl orange or phenolphthalein indicator.
The end-point is taken when a drop of KMnO 4 solution imparts a light pink colour to
the mixture in the conical flask.
Discussion of Comparison
Group
Molarity (M)
Concentration (gdm-3)
0.0196
3.0968
0.0199
3.136
0.0197
3.1126
0.0199
3.136
0.0197
3.113
0.0199
3.144
Average
0.0198
3.1231
In the experiment, we have to do titration of KMnO 4 solution and iron (II) ammonium
sulphate solution twice to obtain an average reading of molarity and concentration of
KMnO4 solution.
The percentage error is,
achieved the experiment result although we have a slightly error and the causes of
different results. For instance, the result is different because of the volume of KMnO 4
solution used is not fixed, the end-point of the titration, and the rate of swirling of the
conical flask.
Conclusion
In the experiment, the molarity and concentration of KMnO 4 solution is 0.0196M and
3.0968 gdm-3 respectively. Theoretically, it is 0.0198M and 3.1231 gdm -3. This makes
the percentage error is just 0.8.
From this experiment, I have learn to calculate the oxidation number of an ion, to
complete the unbalanced half-ionic equation and manage to achieve experiment
result with small percentage error.
Safety
1.
2.
3.
Care was taken to avoid any contact with KMnO 4 solution as the colour of
the solution will stain on lab coat, skin etc.
Care was taken not to overshoot the endpoint.
Lab coat and covered shoes were wore during in the lab.
Question
1. a)
b)
Answer
1.
a)
(i)
Fe2+ + e- Fe3+
(ii)
b)
2.
(i)
Molarity of KMnO4- :
MA(20.45)
1
0.1(20.00)
5
MA 0.0196M
(ii)
3.
Oxidation number of Mn
Before:
4.
+7 +2 (reducing- reduction
Mn + 4O = -1
happened)
Mn + 4(-2) = -1
Mn = +7
After: +2