Experiment no.
er Titra
rd ti
a o
n
W
Group 3: Bantigue, Benedicto, Binag
Group 4: Buere, Canlas, Capulong
Let's have a brief background about:
Warder
Titration!
is the simultaneous determination of
sodium hydroxide and carbonate.
also known as double indicators acid-
base titration.
ives
c
t To determine the individual
e
concentration of mixture
jb
ingredients
o
To understand the neutralization
reactions
ives
c
t To understand the concept of an
e
acid-base titration
jb
To understand the concept of
o
double indicator method in
acid-base titration
Methodology
Materials
Chemicals
25-mL of 0.2 M Sodium hydroxide,
NaOH NaOH/
Na2CO3
Methyl
orange
25-mL of 0.2 M Sodium carbonate,
Na2CO3
HCl ph.ph
5 drops of Phenolphthalein
5 drops of Methyl orange
0.2 M Hydrochloric acid, HCl
Materials
Glasswares
Funnel
Washing bottles
Plastic droppers
50-mL glass burette
250-mL conical flask (erlenmeyer flask)
Micropipettes (25-mL)
ice bath
Glass burettes held in a stand
Chemical
Hazard
Risk
Assessment
trol measur
n es
Co :
Nitrile gloves
Lab goggles
Lab coat Facemask
Burette
Wash
PROCEDURES
- distilled water (twice)
- 0.2 M HCl soln (once)
Fill with 0.2 M HCl
Burette with
0.2 M HCl
Note:
record initial
Make sure to be in a sharp
volume vertical position.
make sure that the tip of the
Titrant
burette is not empty so as
not to get false results.
Titrating using
Titrating using Phenolphthalein
Phenolphthalein Indicator
Indicator
25 mL of sample
Colorless soln
transfer into 250 mL
(endpoint)
conical flask
(use bulb or graduated
pipette.) record final volume
record the volume of HCl
Colorless soln
(VHCl1)
+5 drops of Phenolphthalein continuation on
indicator
swirl next slide
Intense Pink soln
Caution:
cool in ice bath Do not shake
vigorously
+ 0.2 M HCl (slowly)
shake slowly
Titrating using
Titrating using Methyl
Methyl Orange
Orange Indicator
Indicator
Orange- colored soln
Colorless soln
(endpoint)
(endpoint from the
record final volume
previous titration)
record the volume of HCl
+5 drops of Methyl Orange (VHCl2)
indicator do 2 more trials
swirl
3 concordant
Straw Yellow- colored readings
soln
Note:
+ 0.2 M HCl (slowly) If you got a red
shake slowly colored soln then you
have passed the end
point.
AND RESU
TA LT
A S
D
DATA AND RESULTS
ALCULATIONS
C
for Phenolphthalein
Vol. of HCl used (VHCl1) = Final Vol HCl -Initial Vol HCl
Trial 1 Trial 2 Trial 3
Final Vol 10.23 mL 10.28 mL 10.20 mL
Initial Vol
0.00 mL 0.00 mL 0.00 mL
(VHCl1) 10.23 mL 10.28 mL 10.20 mL
ALCULATIONS
C
for Phenolphthalein
Average Volume HCl = [Trial 1 (VHCl1) +Trial 2 (VHCl1) + Trial 3 (VHCl1) ] 3
10.23 mL + 10.28 mL + 10.20 mL
Average Vol. = 10.24 mL
ALCULATIONS
C
for Methyl Orange
Vol. of HCl used (VHCl2) = Final Vol HCl -Initial Vol HCl
Trial 1 Trial 2 Trial 3
Final Vol
25.60 mL 25.55 mL 25.58 mL
Initial Vol
10.23 mL 10.28 mL 10.20 mL
(VHCl2) 15.37 mL 15.27mL 15.38 mL
ALCULATIONS
C
for Methyl Orange
Average Volume HCl = [Trial 1 (VHCl2) +Trial 2 (VHCl2) + Trial 3 (VHCl2) ] 3
15.37 mL + 15.27 mL + 15.38 mL
Average Vol. = 15.34 mL
Treatment of
Results
Identify whether your sample contains:
sodium carbonate and sodium
hydroxide,
or sodium carbonate and sodium
bicarbonate,
or only sodium carbonate.
Indicators
pH
Indicators
pH
Indicators
pH
What we wanted is an
orangey-red solution
If you got a red-colored sol'n
then you have passed the end
point.
1
2
3
4
5
To determine the composition, let's check the graph
Titration pH range
Phenolphthalein (8.3 - 10) Methyl Orange (3.1 - 4.4)
To determine the composition, let's check the graph
Titration pH range
Phenolphthalein (8.3 - 10) Methyl Orange (3.1 - 4.4)
To determine the composition, let's check the graph
Titration pH range
Phenolphthalein (8.3 - 10) Methyl Orange (3.1 - 4.4)
To determine the composition, let's check the graph
Average volume of HCl used during
the titration with phenolphthalein
= 10.24 mL
Titration pH range
Phenolphthalein (8.3 - 10) Methyl Orange (3.1 - 4.4)
To determine the composition, let's check the graph
Average volume of HCl used during
the titration with phenolphthalein
= 10.24 mL
10.24 mL
Titration pH range
Phenolphthalein (8.3 - 10) Methyl Orange (3.1 - 4.4)
To determine the composition, let's check the graph
Average volume of HCl used during
the titration with phenolphthalein
= 10.24 mL
Average volume of HCl used during
10.24 mL the titration with methyl orange
= 15.34 mL
Titration pH range
Phenolphthalein (8.3 - 10) Methyl Orange (3.1 - 4.4)
To determine the composition, let's check the graph
Average volume of HCl used during
the titration with phenolphthalein
= 10.24 mL
Average volume of HCl used during
10.24 mL the titration with methyl orange
= 15.34 mL
15.34 mL
Titration pH range
Phenolphthalein (8.3 - 10) Methyl Orange (3.1 - 4.4)
To determine the composition, let's check the graph
Take Note:
V(m.o) is measured from
the first endpoint, not
10.24 mL from the start of titration
15.34 mL
To determine the composition, let's check the graph
Take Note:
V(m.o) is measured from
the first endpoint, not
10.24 mL from the start of titration
15.34 mL
To determine the composition, let's check the graph
Take Note:
V(m.o) is measured from
the first endpoint, not
10.24 mL from the start of titration
15.34 mL
Since;
V(phth) < V(m.o)
Methyl Orange
Phenolphthalein
To determine the composition, let's check the graph
Take Note:
V(m.o) is measured from
the first endpoint, not
10.24 mL from the start of titration
15.34 mL
Since;
V(phth) < V(m.o)
V0 V1 Methyl Orange V2 V0 to V1 < V1 to V2
Phenolphthalein
What are the
components found
in the sample?
SOdium Carbonate SOdium BiCarbonate
Given that, Vphth<VMO
Calculate the
concentration of each
component (sodium
hydroxide, sodium
carbonate, sodium
bicarbonate). Show your
calculations.
culations
Cal
Can you
Determine whether the solution contains sodium
determine the
hydroxide, sodium carbonate, or sodium bicarbonate
exact contents
(volumes of each indicator’s end point)
of a mixture if it
- NaOH – Vphth
contains sodium
- Na2CO3 – Vphth & VM.O. (equal)
carbonate,
- NaHCO3 – VM.O.
sodium
Phenolphthalein end point contents: NaOH & Na2CO3
hydroxide, and Methyl orange end point contents: Na2CO3 & NaHCO3
sodium First end point (Na2CO3 or NaOH)
bicarbonate - If 0 to V1 > V1 to V2 – NaOH
using Warder - If 0 to V1 < V1 to V2 – Na2CO3
titration? Second end point (Na2CO3 or NaHCO3)
Explain your - 0 to V1 > V1 to V2 – Na2CO3
answer. - 0 to V1 < V1 to V2 – NaHCO3
DATA AND RESULTS
You
!
k
n
a
hT
REFERENCES:
emistry La
al Ch bo
tic ra
ly to
a ry
n
A
1 Chem 2
CONCLUSION
Treat everyone with kindness and
respect, online and offline.
A AND RESUL
AT TS
D ethyl oran
or m ge
f
Trial 1 Trial 2 Trial 3
Initial Vol. of HCl 0 mL 0 mL 0 mL
Final Vol. of HCl
22.5 mL 22.4 mL 22.6 mL
Vol. of HCl used
22.5 mL 22.4 mL 22.6 mL
Average vol. 22.5 mL
A AND RESUL
AT TS
D henolphtha
r p lei
o n
f
Trial 1 Trial 2 Trial 3
Initial Vol. of HCl 0 mL 0 mL 0 mL
Final Vol. of HCl
17.4 mL 17.5 mL 17.3 mL
Vol. of HCl used
17.4 mL 17.5 mL 17.3 mL
Average vol. 17.4 mL
