Test for the presence of carboxylic acid

1. TEST FOR THE
PRESENCE OF
CARBOXYLIC ACID

2. Litmus Test
Reagents
Result
Carboxylic acid turns
blue litmus red,
indicating it is acidic in
nature

3. Sodium Hydrogen Carbonate Test
Reagents
Result
Carboxylic acids react
with sodium bicarbonate
to produce brisk
effervescence due to the
formation of carbon
dioxide gas

4. Ester Test
Procedure 1
Procedure 2
Reagents

5. Carboxylic acids reacts with
alcohols in the acidic
medium to produce fruity
smelling compound called
ester
Result

6. Conclusion:
Based on the result, firstly in the Litmus Test,
Carboxylic acid turns blue litmus red. The hydroxyl
group in carboxylic is far more acidic than that in
alcohol. In Sodium Hydrogen Carbonate Test,
Carboxylic acids react with sodium hydrogen
carbonate to produce carbon dioxide gas which can
be seen in the form of a brisk effervescence. Lastly in
the Ester Test, Carboxylic acid reacts with alcohol in
presence of conc. sulphuric acid to form esters that
are identified by the presence of a fruity smell.

7. SAPONIFICATION
REACTION

8. Saponification is the process of making
soap. Soaps are made from fats, oils or
their fatty acids. Soap is the sodium salt
of long chain fatty acids which have
cleansing properties in the water.

9. The most common process of making
soap is saponification, in which
triglycerides present in fats and oils
react with alkalis, such saponification,
in which triglycerides present in fats
and oils react with alkalis, such as
sodium hydroxide or potassium
hydroxide to form soap and glycerol.

10. If sodium hydroxide is used as an
alkali, the soap formed is called hard
soap and is used as washing soap. If
the potassium hydroxide is used as
alkali, the soap formed is soft soap
and is used in some liquid hand soaps
and shaving cream.

11. Materials required
• Coconut oil
• 20% sodium hydroxide solution
• Common salt
• Measuring cylinders
• Beakers
• Blue and red litmus paper
• Glass rods
• Filter funnel
• Filter paper
• Iron stand
• Hot plate
• spatula

12. A measuring cylinder was taken, and the beaker
containing coconut oil and 25 ml of coconut oil was
poured into the measuring cylinder then a 250 ml beaker
was transferred. Subsequently the beaker containing
20% sodium hydroxide solution was taken and 30 ml 20%
sodium hydroxide was poured into another measuring
cylinder. After that, it was transferred into the beaker
containing coconut oil. The mixture was stirred using a
glass rod. Then the beaker was touched from the outside
and it was observed that the beaker is warm hence,
reaction between vegetable oil and sodium hydroxide
solution is exothermic.
The procedures:

13. Afterwards, the beaker containing the mixture
was taken and was placed on a hot plate. The
beaker was heated using a hot plate till the
mixture became whitish paste. The white
suspension formed is made up of soap and
glycerol. This process of formation of soap is
called saponification. The beaker was removed
from the flame and allowed it to cool. A red
and blue litmus paper is then placed in the
suspension and turns to or remains blue,
indicating that soap is basic.

14. 15g common salt was taken. It was added into the
suspension and stirred well with a glass rod. After
adding the common salt, soap is precipitated out as
solid. Then a filter paper was placed in the filter
funnel. It was fixed in a stand and a beaker was
placed below the funnel. The contents of the beaker
was poured into the funnel over a glass rod and the
contents of the beaker was filtered. After the
filtration, soap is left behind in the filter paper. The
soap was transferred into another filter paper using a
spatula. It was dried after pressing another filter
paper and the soap was prepared.

15. Conclusion:
The reaction between vegetable oil and sodium
hydroxide solution is exothermic in nature because
heat is liberated during the reaction. The white
suspension formed is made up of soap and glycerol.
The red and blue litmus paper test in which the color
results to blue indicates that the soap is basic. Salt
is added to the suspension and solidifies the mixture.
This mixture is filtered and is then a product of soap.
The process of formation of soap is called
saponification.