Name : Rudi Setiawan

Npm : E1G013100

Study Program : TIP

Group : 3

Day/Hour : Monday / 08.00-09.40

Date : 02-04-2014

LECTURER : Devi silsia, Dra.,

Practical object : IDENTIFICATION OF UNsaturated HYDROCARBON







1.1 Background

Organic compounds containing only hydrogen and carbon atoms are called hydrocarbons. Hydrocarbons are divided into two, namely aliphatic hydrocarbons and cyclic hydrocarbons. Aliphatic and cyclic hydrocarbons are also subdivided into several sections. Aliphatic hydrocarbons are divided into two, namely saturated aliphatic (alkane compounds) and unsaturated aliphatic (alkene and alkyne compounds), while cyclic hydrocarbons are divided into three namely saturated cyclic (cycloalkane), unsaturated cyclic (cycloalkene), and cyclic aromatic (benzene).

The physical properties possessed by hydrocarbons are caused by the non-polar nature of these compounds. Generally, hydrocarbons are immiscible with polar solvents such as water or ethanol. On the other hand, hydrocarbons can be miscible with relatively non-polar solvents such as carbon tetrachloride (CCl .).4) or dichloromethane (CH2Cl2). The chemical reactivity of hydrocarbon compounds is determined by the type of bond. Saturated hydrocarbons (alkanes) are unreactive with most of the reagents. Unsaturated hydrocarbons (alkenes and alkynes), can undergo addition reactions in their double or triple bonds. While aromatic compounds usually undergo substitution reactions. Reaction with KMnO4 (Baeyer test)

KMnO . solution4 oxidize unsaturated compounds. Alkanes and aromatic compounds are generally not reactive with KMnO4. The occurrence of this reaction is indicated by the loss of the purple color of KMnO .4and the formation of a brown MnO . precipitate2. The resulting product is a glycol or 1,2-diol.

From the theoretical basis, several experiments have been carried out to identify hydrocarbon compounds based on the reactions described above. Procedures, tools and materials used.

1.2 the purpose of the experiment

students are able to identify unsaturated hydrocarbon compounds.



The simplest hydrocarbons are alkanes, which are hydrocarbons that contain only single covalent bonds. Hydrocarbons are compounds whose molecular structure consists of hydrogen and carbon. The simplest molecule of alkanes is methane. Methane is a gas at standard temperature and pressure, and is the main component of natural gas.

Hydrocarbons can be classified according to the types of carbon bonds they contain. Hydrocarbons with carbons having one bond are called saturated hydrocarbons. Hydrocarbons with two or more carbon atoms having double or triple bonds are called unsaturated hydrocarbons (Fessenden, 1997).

Hydrogen and its derivatives are generally divided into three major groups, namely:

1. Aliphatic hydrogen consists of carbon chains that do not include cyclic structures. This group is often referred to as open chain hydrocarbons. The aliphatic hydrocarbons include alkanes, alkenes, and alkynes. Examples of aliphatic hydrocarbons are:

C2H6 (ethane) alkane

CH3CH2CH2CH2CH3(pentane) alkane

C3H6(propene) alkene

C4H6(buttuna) alkyne

Alkanes: are saturated hydrocarbons that have the maximum number of hydrogen atoms. General formula CnH2n+2. Its properties include soluble in non-polar solvents and insoluble in polar solvents, can undergo halogenation reactions, etc.

Alkene: is a hydrocarbon compound that has a deficiency of 2 H atoms and has a double bond on the C=C atom. alkenes have the general formula CnH2n and is an unsaturated hydrocarbon. This unsaturated hydrocarbon is isomeric with cycloalkanes. Its properties include insoluble in water but soluble in organic solvents, more reactive than alkanes, etc.

Alkynes are triple hydrocarbon compounds with the general formula CnH2n-2. Alkynes are isomers with alkenes having 2 double bonds or a compound having 1 double bond and 1 cyclic. Its properties include being easy to undergo addition reactions such as alkenes, being able to undergo oxidation reactions, etc

2. Alicyclic hydrocarbons or cyclic hydrocarbons consist of carbon atoms arranged in one or more rings.

3. Aromatic hydrocarbons are a special class of cyclic compounds which are usually described as six rings with alternating single and double bonds. This group is classified separately from acyclic and aliphatic hydrocarbons because of their characteristic physical and chemical properties.

As saturated hydrocarbons, all the carbon atoms in alkanes have four single bonds and no lone pairs of electrons. All electrons are strongly bonded by both atoms. As a result, these compounds are quite stable and are also called paraffins which means they are less reactive (Wilbraham, 1992).

The carbons of a hydrocarbon can be joined as a chain or a ring. Saturated hydrocarbons with their atoms joined in a straight chain or a branched chain are classified as alkanes. A straight chain means that each carbon atom of the alkane will be bonded to no more than two other carbon atoms. An alkane chain contains at least one carbon atom bonded to three or more other carbon atoms (syahril, 2000).

Straight chain alkanes:

CH3– CH2 – CH3

Branched chain alkanes:

CH3 – CH – CH2 – CH3


Compounds with low molecular weights are gases and liquids, and substances with high molecular weights are solids. Alkanes are nonpolar substances, substances that are insoluble in water with a liquid density of less than 1.0 g/ml. In addition to alkanes, there are also alkenes, which are hydrocarbons that have one or more carbon-carbon double bonds. This compound is said to be unsaturated because it does not have a maximum number of atoms that can actually be accommodated by each carbon (Pettruci, 1987).



3.1 tools and materials

Tools used

Spray bottle

100 ml cup

100 ml and 25 ml measuring cups

Drop pipette

Erlenmeyer 250 ml

Test tube + rack

Test tube clamp

Pipette volume5 ml

Materials used




Plastic pipe/hose


3.2 working procedures

· Alkene oxidation reaction

1. The sample is put into a test tube as much as 5 ml

2. Add 1% KMn04 solution drop by drop into the test tube until the color changes

3. If the sample color changes to clear, it indicates the sample contains unsaturated carbon compounds.

· Acetylene formation reaction

1. Enter the carbide(cac2) as large as corn into an Erlenmeyer with a volume of 250 ml which was previously filled with 100 ml of distilled water.

2. Next cover with rubber / cork that has been perforated.

3. Insert a long glass pipe / hose into the Erlenmeyer which has been covered with cork earlier.

4. Stream the end of the glass pipe / hose into another Erlenmeyer which already contains 1% KMn04 solution

5. If the color of KMn04 is gone, it means it contains acetylene gas



4.1 observations



Observation result



Experiment 4.2.1

Alkene oxidation reaction (bayer test)

The color of the kmn04 compound is not clear

Has saturated carbon


Experiment 4.2.2

Acetylene formation reaction

The color of kmn04 changes to brown

Kmn04 to acetylene

4.2 discussion

Hydrocarbons are the simplest carbon compounds. From the name, hydrocarbon compounds are carbon compounds that are only composed of hydrogen atoms and carbon atoms. This identification of hydrocarbon compounds aims to investigate the physical properties, solubility and density of hydrocarbon compounds, to compare the reactivity between alkanes, alkenes, and aromatic compounds, to use physical and chemical properties to identify unknown compounds. The samples used were cyclohexane, toluene and unknown samples (phenol).

Cycloalkanes are saturated hydrocarbons containing CH bonds and CC single bonds, only the carbon atoms are joined in a ring. Meanwhile, toluene is an aromatic hydrocarbon. At the time of testing the physical properties, when cyclohexane, toluene and unknown substances were added with insoluble distilled water. This is because the density of water is greater than the sample so that the sample is in the upper layer. Judging from the dipole moment, water and cyclohexane have very different values, namely cyclohexane.

At the time of testing the chemical properties was carried out by reacting the sample with bromine, permanganate and concentrated sulfuric acid. At first, when added with a few drops of bromine contained in n-hexane, the cyclohexane sample solution did not act but only changed color to become slightly brownish and seemed to form a precipitate. Though it does not precipitate but has a higher density than the solvent. Then, toluene is added with Br2 but no reaction occurs because Br2 is a volatile solvent. So when added to the sample, Br2 already evaporated. And when an un known substance is added a few drops with Br2no reaction occurs.

Then the sample is added with KMnO4, cyclohexane does not react and remains a purple color. Because cyclohexane is saturated so it cannot react. However, when toluene and samples of unknown substances (Phenol) can act with a change to a slightly brown. This is because the double bond in phenol or benzene has a double bond resonating.



6.1 conclusion

Hydrocarbons are the simplest carbon compounds. From the name, hydrocarbon compounds are carbon compounds that are only composed of hydrogen atoms and carbon atoms. This identification of hydrocarbon compounds aims to investigate the physical properties, solubility and density of hydrocarbon compounds, and when conducting experiments using KMn04 the reaction becomes brownish. Hydrocarbons can be classified according to the types of carbon bonds they contain.

6.2 suggestions

My suggestion is that when practicing, the available materials must be met or present so that they can practice well.


Fessenden, 1997.Compounds of carbon and hydrogen.erlangga.jakarta.

Pettruci, 1987.Hydrocarbons in nature.

syahril, 2000. Benefits of hydrocarbons. Gajah Mada University Press: Yogyakarta.

Wilbraham, 1992.Definition of hydrocarbon compounds.. Jakarta: Lepdikbud