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Table 1. Preparation of Alkane (Methane)

Sample DescriptionReagents: (soda lime) (anhydrous CH3COONa)

White powderWhite powder

Mixture White powderProduct: (methane) (Na2CO3)

Chemical Equation:

1. CH3COONa+NaOH CH4 + Na2CO3

Table 2. Preparation of Alkyne (Acetylene)

Sample DescriptionReagents: (Calcium carbide) (water)MixtureProducts: (Ca(OH2)) (C2H2)

Chemical Equation:

1. CH3COONa+NaOH CH4 + Na2CO3

Table 3. Solubility of Hydrocarbons in Water

Name/Structure Description of sample + water Solubility (+/-)AlkaneAlkyneAromatic Hydrocarbon

General ConclusionExplanation

Table 4. Bromination: Electrophillic Addition of

Sample (name) Description Chemical rxnSaturated Hydrocarbon(

4a

Unsaturated Hydrocarbon(

4b

Chemical Equation

4a4b

Table 5. Oxidizability: Oxidation with

Sample (name) Description Chemical rxnSaturated hydrocarbon(

5a

Unsaturated hydrocarbon(

5b

Aromatic hydrocarbon(

5c

Chemical Equation

5a5b5c

Table 6. Ignition Test (reaction test )

Sample(name) Description Chemical rxnSaturated Hydrocarbon(

6a

Unsaturated Hydrocarbon(

6b

Aromatic Hydrocarbon (

6c

Chemical Equation

6a CH4 + O2 CO2 + CO + H2O6b C₂H + ₂ O2 CO2 + CO + H2O6c C6H6 + O2 CO2 + CO + H2O

Discussion

In the first part, which is saturated hydrocarbon, the methane was prepared. 3 g of soda lime and 6 g of anhydrous CH3COONa were ground. Sodium acetate is heated with soda lime (three parts Calcium oxide, one part sodium Hydroxide), methane gas is produced. Sodium Hydroxide acts as reactant and Calcium Oxide keeps the gas dry. A mixture of sodium acetate and soda lime are taken in a glass tube and heated. Methane gas is evolved which is collected by downward displacement of water. The downward displacement method makes other soluble gases or salts evaporating from the tube to be absorbed. Methane is insoluble in water,

so the downward displacement technique can be usefully employed. Methane burns in air with a blue flame. In sufficient amount of oxygen, methane burns to give carbon dioxide and water. In insufficient oxygen it gives out carbon monoxide. Methane produces a good amount of heat when it undergoes combustion. This is the reason why it is used as fuel.

Second part is the unsaturation test. First is the bromine test. CH2Cl2 was added to one test tube of gas containing bromine. The color of the solution is light yellow, this indicates that no reaction occurred. Bromine does not react with an alkane because the alkane contains only single C-C bonds which cannot add the bromine. Alkanes merely dilute the red-brown bromine color to an orange or yellow color in the absence of a strong catalyst. In the reaction with alkaline permanganate, 1 mL of 0.0002M KMnO4 solution was added to the second test tube of gas with Na2CO3. If the color of KMnO4 was changed it is cyclohexene and if no change in color of KMnO4 it is alkane or aromatic hydrocarbon. The color of the solution was red, which means its cyclohexene. In the ignition test, the color of the flame is yellow.

Third is the unsaturated hydrocarbon. In preparation of acetylene, a 50 mL test tube was filled with water. Small pieces of calcium carbide was added. This was then connected to a water trough using a delivery tube. In the water trough, three test tube was filled with the acetylene gas when it was heated. Preparing the acetylene undergo addition reactions. First step reduces the carbon-carbon triple bond to carbon-carbon double bond (alkene). Second reduces the double bond to a carbon-carbon single bond (alkane). The acetylene gas is insoluble in water.

Third is the Aromatic hydrocarbon. In the solubility test, two drops of benzene was added to one mL of water. Benzene remained on top. This is because benzene is immiscible & lighter than water. In the test for saturation, ½ mL of 0.0002M KMnO4 was added to ½ mL of benzene. There was no reaction. The potassium permanganate remained on the bottom and its color was purple while the benzene remained on top with its appearance of clear liquid. This is because stabilization due to aromaticity makes benzene significantly less reactive than isolated alkenes. In the ignition test, benzene was ignited. Benzene is flammable so when it was ignited, fire will be produced and then black soot will appear. The color of the flame is yellow, which means its luminous flame. This also means that benzene is aromatic. There was smoke. Smoke produced is the left over incomplete combustion solid products and is also called ―soot. The more or darker smoke comes from a cooler flame where combustion is limited.

Conclusion

Hydrocarbons are those organic molecules that have only hydrogen and carbon. Saturated hydrocarbons have only single bonds (alkanes, no double or triple bonds). The term saturated means that it has the maximum number of atoms attached to each carbon. Methane burns in air with a blue flame. In sufficient amount of oxygen, methane burns to give carbon dioxide and water. In insufficient oxygen it gives out carbon monoxide. Unsaturated hydrocarbons, (not saturated with H’s) like alkenes and alkynes, not only burn, but also react by an addition reaction at the double or triple bond. No reaction occurred in the bromine water test and also the potassium permanganate test, reaction occurred, the color changed. From purple to

red. Its considered as cyclohexene. The gas produced in the preparation of acetylene is insoluble in water. Benzene is also immiscible and lighter than water.

References:

http://reactionsoforganiccompounds.blogspot.com/2010/03/ignition-test-for-benzene.html

http://www.ausetute.com.au/combusta.html

https://answers.yahoo.com/question/index?qid=20070805054235AAWjrWH