Table 4: Protocols for carrying out qualitative test on carboxylic acid and phenol S/N Protocol 1. Observation Inference 1 and J were suspected to Sample I was dropped on a blue itmus paper. Sample J was also dropped on a different blue litmus paper be benzoic acid and phenol 2 3 ml of sample I was put into a dry test tube 1 was suspected to be and 2 ml of ethyl alcohol was added, followed by 2 ml of concentrated H;SO. The phenol mixture was heated in a water bath. 3 mi of sample J was put into a test tube and Brisk effervescence of a gas was evolved 1 ml of saturated NaHCO, was added. The 3. mixture was shaken thoroughly using a rubber cork. 4. No visible reaction occurred 1. Suspected to be was phenol 5. Sweet smelling substance was sensed suspected to be was benzoic acid 1. was confirmed to be Colour of mixture changed to green 6. phenol be was confirmed to benzoic acid 7. 3 ml of sample J was put into a test tube and 100 mg of resorcinol and 0.5 ml of H2SO. were added. The mixture was heated gently on a Bunsen burner. The mixture was then poured into a beaker containing dilute NaOH solution. 2. Propose a balanced chemical equation for item 3 3. Propose a balanced chemical equation for item 5
Table 4: Protocols for carrying out qualitative test on carboxylic acid and phenol S/N Protocol 1. Observation Inference 1 and J were suspected to Sample I was dropped on a blue itmus paper. Sample J was also dropped on a different blue litmus paper be benzoic acid and phenol 2 3 ml of sample I was put into a dry test tube 1 was suspected to be and 2 ml of ethyl alcohol was added, followed by 2 ml of concentrated H;SO. The phenol mixture was heated in a water bath. 3 mi of sample J was put into a test tube and Brisk effervescence of a gas was evolved 1 ml of saturated NaHCO, was added. The 3. mixture was shaken thoroughly using a rubber cork. 4. No visible reaction occurred 1. Suspected to be was phenol 5. Sweet smelling substance was sensed suspected to be was benzoic acid 1. was confirmed to be Colour of mixture changed to green 6. phenol be was confirmed to benzoic acid 7. 3 ml of sample J was put into a test tube and 100 mg of resorcinol and 0.5 ml of H2SO. were added. The mixture was heated gently on a Bunsen burner. The mixture was then poured into a beaker containing dilute NaOH solution. 2. Propose a balanced chemical equation for item 3 3. Propose a balanced chemical equation for item 5
Chemistry for Today: General, Organic, and Biochemistry
9th Edition
ISBN:9781305960060
Author:Spencer L. Seager, Michael R. Slabaugh, Maren S. Hansen
Publisher:Spencer L. Seager, Michael R. Slabaugh, Maren S. Hansen
Chapter15: Carboxylic Acids And Esters
Section: Chapter Questions
Problem 15.39E
Related questions
Question
![Carboxylic acids
are versatile organic compounds, They have excellent physical and
chemical
properties.
The carboxylic acid
chemical structure contains
a carbonyl
functional group and a hydroxyl group. It interacts easily with polar compounds and
contributes to many important chemical reactions.
The carboxylic acid is
the most
important functional group that present C O.
THEORY
Carboxylic acids have tendency to donate protons and they act as acids. It is this
property which is helpful in the identification of a - COOH group. Qualitative tests that
can be performed to identify carboxylic functional group include litmus test, sodium
bicarbonate test or sodium hydrogen carbonate test, ester test and Fluorescein test.
Litmus test.
The carboxylic acid turns blue litmus paper red. Because the hydroxyl group present in -
COOH is far acidic than in alcohol. The chemical reaction is given below.
R-COOH +H2 O R- COO-+ H3O+
If the colour of the blue litmus paper changes to red then carboxylic group is present.
Phenol produce positive results with this test.
Sodium bicarbonate test:
When carboxylic acid reacts with sodium bicarbonate solution, carbon dioxide is
evolved with a brisk effervescence along with the formation of sodium acetate.
The chemical reaction is given below.
RCOOH + NaHCOs - RCOONa + H20 + CO21 (brisk effervescence)
This test is used to distinguish between carboxylic acid from phenol. Phenol does not
give positive results with this test.
3.
Ester test
Carboxylic acid reacts with alcohol in the presence of concentrated sulfuric acid forms a
pleasant-smelling ester. This reaction is known as esterification. Formation of a sweet-
smelling compound indicates the presence of carboxylic group in the given organic
compound.
Reaction: RCOOH + R-OH + H2SO4 RO OO-R (ester) + H2O
4.
Fluorescein test
This test is carried on dicarboxylic acid. Dicarboxylic acid on heating gives acid
anhydride
When this anhydride
is treated with resorcinol in
the presence of
concentrated sulfuric acid, a fluoresscent dye is formed and so this reaction is called
fluorescein test. This test should be performed only if the oompound gives positive
results in litmus test and sodium bicart
te test.
Reagents and apparatus needed to perforn qualitative test on carboxylic acids and
phenols are blue litmus paper, sodium bicarbonate (or) sodium hydrogen carbonate,
ethyl alcohol, concentrated sulfuric acid, resorcinol, acid anhydride, test tubes, test tube
holders, beaker, glass rod and stirrer.
CASE STUDY
The Quality Control and Assurance Department of Ghana Standard Authority (GSA)
identified two organic solvents in their storeroom with their labels torn but suspected to
be benzoic acid and phenol. To ascertain if indeed the organic solvents are benzoic
acid and phenol, qualitative test was carried out on the organic solvents. For easy
identification, the solvents were labeled as I and J. The protocols used for the qualitative
Carefully study Table 4 and
analysis and the observations made are shown in Table 4.
fill in the empty spaces provided. Answer the follow- up questions.
1.
Itemise one industrial application of benzoic acid and phenol.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F2949e4b3-5c71-4158-b4a4-d8ce3951f0d6%2F2244a643-6e70-4897-9f1b-24322997e773%2Fu89jvx_processed.jpeg&w=3840&q=75)
Transcribed Image Text:Carboxylic acids
are versatile organic compounds, They have excellent physical and
chemical
properties.
The carboxylic acid
chemical structure contains
a carbonyl
functional group and a hydroxyl group. It interacts easily with polar compounds and
contributes to many important chemical reactions.
The carboxylic acid is
the most
important functional group that present C O.
THEORY
Carboxylic acids have tendency to donate protons and they act as acids. It is this
property which is helpful in the identification of a - COOH group. Qualitative tests that
can be performed to identify carboxylic functional group include litmus test, sodium
bicarbonate test or sodium hydrogen carbonate test, ester test and Fluorescein test.
Litmus test.
The carboxylic acid turns blue litmus paper red. Because the hydroxyl group present in -
COOH is far acidic than in alcohol. The chemical reaction is given below.
R-COOH +H2 O R- COO-+ H3O+
If the colour of the blue litmus paper changes to red then carboxylic group is present.
Phenol produce positive results with this test.
Sodium bicarbonate test:
When carboxylic acid reacts with sodium bicarbonate solution, carbon dioxide is
evolved with a brisk effervescence along with the formation of sodium acetate.
The chemical reaction is given below.
RCOOH + NaHCOs - RCOONa + H20 + CO21 (brisk effervescence)
This test is used to distinguish between carboxylic acid from phenol. Phenol does not
give positive results with this test.
3.
Ester test
Carboxylic acid reacts with alcohol in the presence of concentrated sulfuric acid forms a
pleasant-smelling ester. This reaction is known as esterification. Formation of a sweet-
smelling compound indicates the presence of carboxylic group in the given organic
compound.
Reaction: RCOOH + R-OH + H2SO4 RO OO-R (ester) + H2O
4.
Fluorescein test
This test is carried on dicarboxylic acid. Dicarboxylic acid on heating gives acid
anhydride
When this anhydride
is treated with resorcinol in
the presence of
concentrated sulfuric acid, a fluoresscent dye is formed and so this reaction is called
fluorescein test. This test should be performed only if the oompound gives positive
results in litmus test and sodium bicart
te test.
Reagents and apparatus needed to perforn qualitative test on carboxylic acids and
phenols are blue litmus paper, sodium bicarbonate (or) sodium hydrogen carbonate,
ethyl alcohol, concentrated sulfuric acid, resorcinol, acid anhydride, test tubes, test tube
holders, beaker, glass rod and stirrer.
CASE STUDY
The Quality Control and Assurance Department of Ghana Standard Authority (GSA)
identified two organic solvents in their storeroom with their labels torn but suspected to
be benzoic acid and phenol. To ascertain if indeed the organic solvents are benzoic
acid and phenol, qualitative test was carried out on the organic solvents. For easy
identification, the solvents were labeled as I and J. The protocols used for the qualitative
Carefully study Table 4 and
analysis and the observations made are shown in Table 4.
fill in the empty spaces provided. Answer the follow- up questions.
1.
Itemise one industrial application of benzoic acid and phenol.
![Table 4: Protocols for carrying out qualitative test on carboxylic acid and phenol
S/N Protocol
Observation
Sample I was dropped on a blue litmus
Inference
paper. Sample J was also dropped on a
and J were suspected to
different blue litmus paper
be benzoic acid and phenol
3 ml of sample I was put into a dry test tube
and
2 ml of ethyl alcohol was added,
I was suspected to be
phenol
followed by 2 mi of concentrated H;SO. The
mixture was heated in a water bath.
3 ml of sample J was put into a test tube and
1 ml of saturated NaHCO, was added. The
Brisk effervescence of a gas was evolved
mixture was shaken thoroughly using a
rubber cork
4.
No visible reaction occurred
I was
suspected to be
phenol
5.
Sweet smelling substance was sensed
suspected to be
was
benzoic acid
was
confirmed to
Colour of mixture changed to green
6.
phenol
was confirmed
to
be
benzoic acid.
7.
3 ml of sample J was put into a test tube and
100 mg of resorcinol and 0.5 ml of H2SO4
were added. The mixture was heated gently
on a Bunsen burner. The mixture was then
poured into a beaker containing dilute NaOH
solution.
2. Propose a balanced chemical equation for item 3
3. Propose a balanced chemical equation for item 5
4. State two precautionary measures adopted to ensure that protocol 3 in Table 4 was carried out successfully
5. With the aid of a diagram describe an experiment that could be done to confirm that the gas evolved in item 3 is
carbon (iv) oxide](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F2949e4b3-5c71-4158-b4a4-d8ce3951f0d6%2F2244a643-6e70-4897-9f1b-24322997e773%2Fjaraze9_processed.jpeg&w=3840&q=75)
Transcribed Image Text:Table 4: Protocols for carrying out qualitative test on carboxylic acid and phenol
S/N Protocol
Observation
Sample I was dropped on a blue litmus
Inference
paper. Sample J was also dropped on a
and J were suspected to
different blue litmus paper
be benzoic acid and phenol
3 ml of sample I was put into a dry test tube
and
2 ml of ethyl alcohol was added,
I was suspected to be
phenol
followed by 2 mi of concentrated H;SO. The
mixture was heated in a water bath.
3 ml of sample J was put into a test tube and
1 ml of saturated NaHCO, was added. The
Brisk effervescence of a gas was evolved
mixture was shaken thoroughly using a
rubber cork
4.
No visible reaction occurred
I was
suspected to be
phenol
5.
Sweet smelling substance was sensed
suspected to be
was
benzoic acid
was
confirmed to
Colour of mixture changed to green
6.
phenol
was confirmed
to
be
benzoic acid.
7.
3 ml of sample J was put into a test tube and
100 mg of resorcinol and 0.5 ml of H2SO4
were added. The mixture was heated gently
on a Bunsen burner. The mixture was then
poured into a beaker containing dilute NaOH
solution.
2. Propose a balanced chemical equation for item 3
3. Propose a balanced chemical equation for item 5
4. State two precautionary measures adopted to ensure that protocol 3 in Table 4 was carried out successfully
5. With the aid of a diagram describe an experiment that could be done to confirm that the gas evolved in item 3 is
carbon (iv) oxide
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