EXERCISE 1
PROPERTIES THAT DISTINGUISH ORGANIC FROM INORGANIC COMPOUNDS
Organic Compounds
Inorganic Compound
Flammable
yes
no
Melting Point
low
high
Boiling Point
low
high
Solubility in water
no (for most)
yes
Solubility in non-polar liquids
yes
no
Type of bonding
covalent
ionic
Reactions occur between:
molecules
ions
Atoms per molecule
many
few
Structure
complex
simple
Electrolyte
no
yes
 Organic compounds are unstable. They are combustible, with many having no sharp
melting points, decomposing, and charring at moderately high temperature.
 Most are non-electrolytes.
 Most organic compounds contain the same kind and number of atoms but they exhibit
different sets of properties.
 Organic chemical reactions are relatively slow.
Name of Test
Ignition Tests
a. Flammability
b. Charring
Test Compound
Result
Ethyl alcohol
Water
Sucrose
Flammable
Non-flammable
Positive
C12H22O11 + O2 + heat → CO2↑ + 11H2O↑ + 11C↓
Sodium chloride
Calcium carbonate
Negative
Negative
Name of Test
Solubility Tests
Test Compound
Naphthalene in water
Naphthalene in ether
Urea in water
Urea in ether
Sodium chloride in water
Sodium chloride in ether
Name of Test
Electrical Conductivity
Observation
Insoluble
Soluble
Partially soluble
Soluble
Soluble
Insoluble
Test Compound
1M sucrose
1M sodium chloride
95% ethyl alcohol
n-hexane
Type of Bond
Covalent bond
H-bonding
Covalent bond
Ionic bond
Observation
Non-electrolyte
Electrolyte
Non-electrolyte
Non-electrolyte
EXERCISE 2
QUALITATIVE TESTS FOR ELEMENTS IN ORGANIC COMPOUNDS
 Carbon and hydrogen are the predominant elements found in organic compounds.
 Next common elements are: oxygen, nitrogen, sulfur, phosphorus, halogens – chlorine,
bromine, and iodine.
 Least common elements include: arsenic, antimony, mercury, and other metals.
A. Test for Carbon and Hydrogen
Test compound: Glucose (C6H12O6)
 Carbon and hydrogen are detected qualitatively by heating a mixture of the given substance
with dry copper (II) oxide in a glass tube.
C6H12O6 + CuO → CO2↑ + H2O
CO2 + Ca(OH)2 → CaCO3↓ + H2O
Glucose + CuO
heat
CO2
water vapor
gets trapped in lime water
Calcium carbonate
Water
 The presence of carbon is indicated by the formation of white precipitate.
 The presence of hydrogen is indicated by the formation of droplets of water in the cool end
of the tube.
 Copper (II) oxide acts as a catalyst.
B. Test for Nitrogen
Name of test: Soda-Lime Test
Test compound: Urea
 Soda-lime: NaOH-CaO (2:1 solid mixture)
 Nitrogen is usually detected by the formation of Prussian blue after the sodium fusion.
CO(NH2)2 + heat → NH3↑ + CO2
CO2 + Ca(OH)2 → CaCO3↓ + H2O
 When heated with soda lime, urea decomposes and the nitrogen in the form of amino
nitrogen (-NH2) will liberate ammonia gas.
 Red litmus paper changes to blue.
C. Test for Halogen
Name of test: Beilstein Test
Test compound: Chloroform (CHCl3)
 An organic halogen compound imparts a green color flame when burned upon the surface
of a copper wire.
 The copper oxide formed from the copper wire reacts with the halogens to form the
cuprous halide, which burns with a green flame.
 Chlorine is the compound responsible for turning the flame green.
Name of test: Silver Nitrate Test
Test compound: Monochloroacetic acid
 Formation of insoluble silver halide upon treatment with silver nitrate in the presence of
dilute nitric acid.
 Nitric acid is necessary to remove cyanide and sulfide ions, otherwise, they form
precipitates – silver cyanide is white and silver sulfide is black – that interfere with the
detection of halogens.
 Silver chloride – white precipitate.
D. Test for Oxygen
Name of test: Ferrox Test
Test compounds: Acetone, ethyl alcohol, gasoline, benzene
 Ferrox paper is prepared by soaking filter paper in methanol containing equal amounts of
ferric chloride and ammonium thiocynate.
 In the presence of oxygen, a deep red color is distributed between the filter paper and the
test compound.
 The test showed positive results for acetone and ethyl alcohol.
E. Test for Sulfur
Name of test: Lead Acetate Test
Test compounds: Albumin
 The presence of sulfur is detected by the production of brownish-black lead sulfide when
albumin is treated with lead acetate in the presence of acetic acid.
 Acetic acid prevents the formation of other insoluble lead salts.
 The production of brownish-black precipitate is due the presence of cysteine – the amino
acid part of albumin.
EXERCISE 3
Separation and Purification of Organic Compounds
QUALITATIVE TESTS FOR ELEMENTS IN ORGANIC COMPOUNDS

Recrystallization is a highly effective method for the purification of organic substances
that exists already as crystals.
Processes Involved in Recrystallization
1. Dissolving the material to form a saturated solution in a suitable solvent at an
elevated temperature.
Properties of a Desirable Solvent
a. Dissolves the solute easily at an elevated temperature, but only sparingly
at a lower temperature.
b. Gives no chemical reaction with the solute.
c. Sufficiently volatile so that it may be removed easily from the purified
crystals.
2. Filtering while hot to remove any suspended insoluble particles.
3. Letting crystallization process
Stages of Recrystallization
1. Removal of impurities, which may retard or inhibit crystal formation.
 Samples that contain colored impurities maybe treated with decolorizing
carbon to give rise to colorless solution.
 Impurities are adsorbed by the active surface of the
decolorizing carbon.
 Animal charcoal is less effective at high than at low
temperature.
 The reason for operating at high temperature is to keep the
substances from being crystallized in solution.
2. Nucleus formation
 Spontaneous nucleus formation is caused by the orientation and aggregation
of sufficient number of molecules, which may give rise to a crystal nucleus.
Methods of Inducing Crystal Formation
1. Seeding – the process of adding a small crystal of pure material to induce
the crystallization process.
2. Scratching the sides or bottom of a container with a glass rod – provides
sharp edges upon which crystal growth may occur.
3. Encouragement of growth of crystals to visible form.
 Growth of crystals maybe encouraged by stirring or agitation, which results in
distribution of the nuclei throughout the solution.
 Crystal growth in supersaturated solutions may be inhibited as
a result of restricted motion of the molecules.
A. Recrystallization of Benzoic Acid
Benzoic acid + NaCl + Methylene blue
heat
+ activated charcoal
filter
activated charcoal + methylene blue
colorless solution
rapid cooling
water
slow cooling
coarse crystals
water
fine crystals
wash with cold distilled water
Benzoic acid crystals
+
hot distilled water
+
HNO3
+
AgNO3
Benzoic acid crystals
+
hot distilled water
+
HNO3
+
AgNO3
Colorless solution
with crystals
Colorless solution
with crystals
Cloudy solution: NaCl + AgNO3 → NaNO3 + AgCl
B. Decolorization of Brown Sugar
Brown sugar
Brown sugar solution
+ water
Brown sugar solution
Heat
+ Activated carbon
filter
activated charcoal + brown pigment
Colorless solution
EXERCISE 4
Separation and Purification of Organic Compounds
SUBLIMATION
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Sublimation – the direct conversion of a substance from solid to gas without passing
through the liquid state.
o It can be applied when the components of a solid mixture differ appreciably in
their vapor pressures.
o As a separation process, it involves gentle heating of the mixture in a confined
container until the component with high vapor pressure changes into vapor
phase, while the component with the lower vapor pressure is left in the
container.
o As a purification process, it also depends on the difference of volatility. Less
volatile or non-volatile impurities remain as residue while the sublimate is being
formed.
Sublimate – the crystals, deposit, or material obtained when a substance is sublimated.
o High vapor pressure
o Low melting point
o More volatile
Residue – the solid particles that remained on the dish.
o Low vapor pressure
o High melting point
o Less or non-volatile
Deposition – the process of changing gas to solid without passing through liquid state.
Salicylic acid – sodium
sulfate mixture
Physical Appearance
Polarity
Type of Compound
Observation


SUBLIMATE
RESIDUE
Salicylic Acid
Sodium sulfate
Needle-like
Non-polar
Organic
Colorless solution with
salicylic acid crystals
Powder-like
Polar
Inorganic
Cloudy solution with white
precipitate
Salicylic acid + BaCl → no reaction
o Salicylic acid is an organic compound, while barium chloride is an inorganic
compound.
Na2SO4 + BaCl → NaCl + BaSO4↓
o Sodium sulfate is a polar inorganic compound that results to white precipitate
(barium sulfate) when added with barium chloride.
EXERCISE 5
Separation and Purification of Organic Compounds
DISTILLATION
 Distillation is usually employed for the purification of liquid organic substances.
 It involves evaporation and condensation.
o Evaporation – the conversion of liquid to vapor state with the aid of heat
o Condensation – the process in which vapor turns to liquid by cooling.
 Distillate – the liquid that passed through the distilling flask.
 It requires a distillation flask fitted with a thermometer and a water-cooled condenser.
 Boiling chips are also used to prevent bumping by producing a constant steam of bubbles
which keeps the liquid in motion.
 Boiling point is one of the most important criteria of purity, as it is constant in every pure
organic substance at a definite pressure.
 Distillation could be used to convert muddy water to potable water.
o Solid particles should be allowed to settle and then decanted. Then, the water
should be heated to boil in low to moderate fire. It should be below the boiling
point of water. This would rid the water of impurities.
 The use of distillation is limited to a certain extent because some organic compounds
decompose when an attempt is made to distill them at normal atmospheric pressure.
Common Types of Distillation
1. Simple Distillation – used to separate a volatile liquid from a non-volatile solute.
– a large temperature difference (more than 20°) between the boiling
points of the component is necessary to obtain efficient separation.
– the component which is more volatile will distill over first, in almost
pure form at a definite constant temperature, the second component will
distill over when the boiling point again remains constant for a long period
of time.
2. Fractional Distillation – the process of collecting separate fractions according to arbitrary
boiling point ranges during the distillation of a mixture of substances.
– It is performed readily by means of a special fractioning column.
– It cannot be used if the components of a mixture have boiling points
very close together because some substances form a “constant boiling
mixture”, also known as azeotropic mixture.
 Azeotropic mixture – a mixture of liquids of certain definite
composition that distills at constant temperature without change
in composition.
4. Diminished-Pressure Distillation
.
5. Steam Distillation
Thermometer
Reading
56°C
100°C
Volume of Distillate
Ignition Test
Sodium-Nitroprusside Test
5 mL
Flammable
Slightly
flammable
Red-wine colored
5 mL
Lighter color
 Sodium-Nitroprusside Test – Clinical test for urine. Test for acetone.
EXERCISE 6
Separation and Purification of Organic Compounds
EXTRACTION OF CHLOROPHYLL
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
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Extraction, by the use of solvents, is a frequently used method of withdrawing or substance
from a mixture.
o It is usually performed using two immiscible solvents. The mixture is first
dissolved in one of the liquids and then shaken with the other to distribute the
components.
Aside from extraction, it also involves decantation and filtration.
o Decantation – the process of separating solid-liquid components of mixtures by
gently pouring out the liquid so as not to disturb the solids that readily settle at
the bottom of the container.
o Filtration – the process of separating the solid from the liquid by using a
porous filter.
 Residue – the solid particles that remained on the filtering medium.
 Filtrate – the liquid that passed through the filtering medium.
Water is usually one of the solvents used in the extraction process.
The other liquid is usually a non-polar organic liquid.
o Diethyl ether – used extensively as an extracting solvent.
– organic solvent
– high solvent power for hydrocarbons and for oxygencontaining compounds.
– Highly volatile. It boils at 34.60°C
– Fire hazard
o Ether – slightly soluble in water
– Its efficiency can be improved by the addition of a small
amount of ionizable salt, such as NaCl.
– The increase polar property of the water solution will cause a
decrease in the solubility of the organic solute.
 Salting-out effect – the reduced solubility in water in
the presence of an electrolyte.
o Petroleum ether
o Ligroin
o Benzene
o Carbon tetrachloride
o Chloroform
o Methylene chloride
o Ethylene dichloride
o N-butanol – slightly soluble in water
Extraction of water-immiscible solvent is useful for isolation of natural products that occur
in animal and plant tissues that have high water content.
Extraction
It acts as an
agitator
Malunggay + sand
grind
-
Non-polar
Extracts chlorophyll
of malunggay
+ hexane + methanol
-
decant
filter
crushed leaves and sand
Has polar and nonpolar end
Water soluble
Absorbs water
It also absorbs other
non-polar substances
of malunggay
green solution
separatory funnel
-
Absorbs traces
of water
-
dark green extract
+
anhydrous sodium sulfate
Non-polar
Chlorophyll
water-methanol solution
EXERCISE 7
Separation and Purification of Organic Compounds
CHROMATOGRAPHY
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Chromatography - the process of separating the substances in a complex mixture by their
different affinities to the adsorbent.
It is one of the most useful methods of separating the components of minute amount of
mixtures.
It used for analyzing mixtures of colored chemicals.
It was invented by a Russian botanist, Mikhail Semyonovich Tsvet, in 1901, while
researching on plant pigments.
This technique involves separation of constituent elements of the mixture.
Chromatography is derived from the Greek words, chroma meaning color, and graphein
meaning to write. Thus, the word chromatography literally means color writing.

It has two phases:
o Stationary Phase – refers to the column packing material and is either solid or
liquid.
- It is usually a piece of high quality filter paper.
o Mobile Phase – represents a mobile phase of liquid or gas.
- The mobile phase is a developing solution that travels up the
stationary phase, carrying the samples with it.

Components of the sample will separate readily according to how strongly they adsorb on
the stationary phase versus how readily they dissolve in the mobile phase.
Different Classification of Chromatographic Methods
1. Adsorption Chromatography (liquid-solid chromatography) – utilizes a mobile liquid or
gaseous phase that is adsorbed onto the surface of a stationary solid phase. The equilibration
between the mobile and stationary phase accounts for the separation of different solutes.
2. Partition Chromatography (liquid-liquid chromatography) – uses a thin film formed on
the surface of a solid support by a liquid stationary phase. Solute equilibrates between the
mobile phase and the stationary liquid.
3. Ion Exchange Chromatography – resin (the stationary solid phase) is used to covalently
attach anions or cations onto it. Solute ions of the opposite charge in the mobile liquid phase
are attracted to the resin by electrostatic forces.
4. Molecular Exclusion Chromatography (gel permeation chromatography) – liquid or
gaseous phase passes through a porous gel which separates the molecules according to its size.
The pores are normally small and exclude the larger solute molecules, but allow smaller
molecules to enter the gel, causing them to flow through a larger volume. This causes the
larger molecules to pass through the column at a faster rate than the smaller ones.

Thin Layer Chromatography – it is usually used as an analytical technique rather than a
preparative method.
o The stationary phase used is an adsorbent in the form of a thin layer of an inert
solid on a supporting material, usually a think sheet of metal or plastic.
o The mobile phase is the solvent system used to separate the components of the
mixture. Hexane and/or ethyl acetate is commonly used.

Paper Chromatography –a method used for testing the purity of compounds and
identifying substances.
Technique:
1. Introduce a small spot of the sample on the filter paper.
2. Put the filter paper into a container that has the mobile phase. Make sure the plate
touches the mobile phase.
3. The solvent moves up the plate due to capillary action and carries the sample upwards.
4. Remove the filter paper and allow it to dry
5. Spray it with ninhydrin to make the spots more visible.

Ruhemann’s Purple - a purple coloration produced by ninhydrin in the presence of an
amino acid.
Calculation of Retention Factor (Rƒ)
Rƒ = distance traveled by the substance_
distance traveled by the solvent
Distance traveled by the solvent = 5.2 cm
Distance traveled by the substance = 3.5 cm
Solvent front
5.2 cm
3.5 cm