IDENTIFICATION OF THE ORGANIC COMPOUNDS AND FUNCTIONAL GROUPS BASED ON OBSERVATIONS
1. Aniline: Brown liquid with a fishy smell (BOARD EXAMINATION 2014 and 2010)
EXPERIMENT
OBSERVATION
INFERENCE
1. Take 1 ml of C-17 in a testA violet / purple colouration
Aniline is confirmed
tube and add a few drops of
solution
water. Now add about 1 ml of
sodium hypochlorite solution;
Shake the contents.
2. Take 1 ml of C-17 in a testtube and add a few drops of
dilute sulphuric acid.
Now add 1 ml of potassium
dichromate solution. Shake and
warm the contents.
A deep red colour turns
blue/green and finally black
solution
Aniline is confirmed
3. Take 1 ml of C-17 in a testtube and add 1 ml of conc.
hydrochloric acid to it. Now, add
a few drops of neutral ferric
chloride solution and dilute the
contents with water
Pale green colouration
Aniline is confirmed
4. Take 2 ml of C-17 and dilute it
with water. To this, add a few
drops of bleaching powder
solution and shake. Now, add a
few drops of ammonium
sulphide solution and shake.
Violet colouration appears which
fades to brown and then green,
with ammonium sulphide
turns intense red
Aniline is confirmed
5. Take 2 ml of C-14 in a test
Red orange dye
Presence of –NH2 group in
tube and add 1 ml of
Aniline is confirmed
concentrated HCl. Cool the
mixture under tap. Shake. Now
add 2 ml of cold 10% solution of
NaNO2.To this mixture add 2 ml
of cold alkaline beta-naphthol
solution.
Deduction: Substance C-17 is Aniline
2. Glucose solution: Colourless solution having no smell (BOARD EXAMINATION 2014 , 2012 , 2010 and
2007 )
EXPERIMENT
OBSERVATION
INFERENCE
1. Take 1 ml of C-16 in a test
A brick red precipitate of
Presence of –CHO group in
tube and add 1 ml of Fehling’s
cuprous oxide
glucose is confirmed.
solution. Warm the contents.
1
2. Take 2 ml of C-16 in a test
tube and add 1 ml of lead
acetate solution followed by 1ml
of ammonium hydroxide
solution. Boil the contents.
White precipitate turns pink
Glucose is confirmed
3. Take 2 ml of C-16 in a test
tube and add 2 to 3 drops of
alcoholic alpha-naphthol
solution. Pour conc. sulphuric
acid slowly along the side of the
test-tube.
A violet -ring at the junction of
two liquids.
Glucose is confirmed
4. Take 2 ml of C-16 in a test
Light pink colour
Glucose is confirmed
tube. To this add a pinch of
resorcinol and 1 ml of
concentrated hydrochloric acid.
Shake the contents and warm
the test tube.
5. Take 2 ml of C-16 in a test
A silver mirror is formed
Presence of –CHO group in
tube and add 1 ml of Tollen’s
glucose is confirmed.
reagent. Warm the contents in a
water bath for about 5 minutes.
6. Take 2 ml of C-16 in a test
Solution turns yellow or dark
Glucose is confirmed
tube and add 1 ml of sodium
brown
hydroxide solution. Boil the
contents.
7. Take 1 ml of C-16 in a test
A black mass is formed. Charring Glucose is confirmed.
tube and add 1 ml of
of sugar
concentrated H2SO4.Warm the
contents of the test tube in a
water bath.
Deduction: Substance C-16 is glucose
3. Acetone: Colourless liquid having the smell resembling nail polish (BOARD EXAMINATION 2011 and
2009))
EXPERIMENT
OBSERVATION
INFERENCE
1. To 2 ml of freshly prepared
A wine red colour which
Acetone is confirmed
sodium nitroprusside solution in changes to violet and then fades
a test tube. To this add 2 ml of
away
C-14 followed by the addition of
caustic soda solution drop by
drop. Warm.
2. Take 2 ml of C-14 in a test
Yellow precipitate which
Acetone is confirmed
tube. To this add 1 ml of
dissolves on shaking with NaOH
mercuric chloride solution. Now
add sodium hydroxide solution
dropwise.Shake.
2
3. Take 1 ml of C-14 in a test
A white crystalline precipitate
Presence of carbonyl group in
tube and add 1 ml of saturated
acetone is confirmed.
solution sodium bisulphite and
shake the mixture well.
4. Take 1 ml of C-14 in a test
Yellow precipitate with
Presence of CH3-CO group in
tube and add a few crystals of
characteristic odour of iodoform acetone is confirmed.
iodine (or a solution of iodine in
KI) Now add 10% NaOH solution
carefully till no further change
take place. Heat the contents on
a water bath for a few minutes
and then allow to cool.
Deduction: Substance C-14 is acetone
4. Formaldehyde: Colourless solution having pungent smell. (BOARD EXAMINATION 2011)
EXPERIMENT
OBSERVATION
INFERENCE
1. Take 2 ml of C-13 in a test
Silver mirror is formed
Presence of –CHO group in
tube. To this add 1 ml of Tollen’s
formaldehyde is confirmed.
reagent. Warm the contents in a
water bath.
2. 1. Take 2 ml of C-13 in a test
White precipitate is formed
Formaldehyde is confirmed.
tube and add 1 g of pyrogallol
which changes to pink and finally
and 1 ml of water. Shake. Add 2
deep red.
ml of concentrated hydrochloric
acid and warm the contents in a
water bath.
3. Take 2 ml of c-13 in a test tube A red ring is formed at the
Formaldehyde is confirmed
and add a few crystals of
junction of the two liquids and a
resorcinol. Shake the contents.
white precipitate is formed in
Slowly add 1 ml of concentrated the aqueous layer.
sulphuric acid along the side of
the test tube.
Deduction; Substance C-13 is formaldehyde (BOARD EXAMINATION 2007 and 2005)
5. Benzoic acid: It is a colourless crystalline solid having no smell.
EXPERIMENT
OBSERVATION
INFERENCE
1. Take 2 ml of C-13 in a test
A fruity smell of ethyl benzoate
Benzoic acid is confirmed.
tube and add 1 ml of ethyl
is obtained
alcohol to it. Then add a few
drops of concentrated sulphuric
acid. Warm the contents of the
test tube in a water bath.
2. Take 2 ml of C-13 in a test
A buff coloured precipitate of
Benzoic acid is confirmed.
tube and add NH4OH soln. drop
ferric benzoate is obtained.
by drop to get a clear solution.
Heat to remove excess of NH3
gas if any, cool and add a few
drops of neutral FeCl3 solution.
3
3. Take 2 ml of 5% solution of
Vigorous effervescence due to
Presence of –COOH group in
NaHCO3 in a test tube and a little the liberation of CO2
benzoic acid is confirmed.
of C-13.
Deduction: Substance C-13 is benzoic acid.
6. Glycerol: It is a colourless, odourless viscous liquid.(BOARD EXAMINATION 2009 and 2005)
EXPERIMENT
OBSERVATION
INFERENCE
1. Take 3 to 4 drops of C-18 in a
Irritating smell of acrolein
Glycerol is confirmed.
test tube. Add about 0.5 gram of
potassium hydrogen sulphate
and heat strongly.
2. Add about 5 ml of water to
Pink colour disappears on adding Glycerol is confirmed.
about 0.2 gram borax in a test
C-18.Reappear on warming and
tube and shake well to get a
disappears on cooling.
clear solution. To the above
solution add 1 to 2 drops of
Phenolphthalein. Now add 2 to 3
drops of the compound
C-18.Shake well again. Warm
and cool.
3. Take 4 to 5 drops of C-18 in a
A deep blue colour
Glycerol is confirmed.
test tube. Add about 1 ml of
copper sulphate solution
followed by a few drops of
sodium hydroxide solution.
4. Take 1 ml of ceric ammonium
A red colour.
Presence of –OH group in
nitrate in a test tube and add 2
glycerol is confirmed.
to 3 drops of C-18 and shake
well.
Deduction: Substance C-18 is glycerol
7. Protein: Colourless and odourless solution.
EXPERIMENT
OBSERVATION
INFERENCE
1. To a little of the solution A add Bluish violet colour
Protein is confirmed.
2 ml of NaOH solution. Now add
5 drops of 1% Copper sulphate
solution.
2. To a little of the solution A add Yellow ppt (Xanthoprotein)
Protein is confirmed.
a few drops of concentrated
HNO3 and heat.
3. To a little of the solution A add Reddish brown ppt
Protein is confirmed
a few drops of Millon’s reagent
and heat gently.
Deduction: The substance A is protein.
4