Ethyne Lab Conclusion

Conclusion:

The five reactions are all oxidation of ethyne gas, which is an alkyne. The first four reaction is oxidizing the alkyne through combustion and the final reaction is through the use of KMnO4. The conclusions for the two sets of reactions, combustion reaction and catalyst driven reaction, is covered individually.

Oxidation of Ethyne through Combustion (Tests #1 to #4, inclusive)

In the first four reactions of the ethyne gas, the result of lighting the gases was a mixture of incomplete and complete combustion for all four tests. Due to the fact that the ethyne gas was placed in an enclosed space, which is the test tube, it does not have as readily of an access to the oxygen present in the room than an open flame. The result was incomplete

The oxidation reaction of ethyne gas is facilitated by potassium permanganate, which is the catalyst in the reaction. The reaction allows ethyne to be oxidized into ethan-1,1,2,2-tetraol by breaking the two pi bonds between the carbons and adding hydroxyl groups. However, the new compound, having 2 hydroxyl groups on each carbon, results in the hydroxyl groups reacting with each other so that two H2O molecules are released and each carbon becomes double-bonded with an oxygen, creating ethandial. The ethandial is further oxidized, through the use of potassium permanganate, to oxalic acid as aldehydes are easily oxidized. No ethandial is preserved as the solution the reaction took place in was not acidic. The oxidation reaction of ethyne created the colour change where the solution turned from dark purple to a reddish brown. The white precipitate and bubble produced were the results of the formation of calcium hydroxide and ethyne in the reaction between the calcium carbide and water, not in the ethyne gas’

First of all, the reactant ethyne used in all of the reactions was the product of another reaction between water and calcium carbide. However, due to the fact that neither the calcium carbide nor the water can be guaranteed to be pure, the reaction to produce ethyne may have created other unwanted by-products. Additionally, as ethyne itself is very reactive, the possibility exists that some ethyne may have reacted with the waste products to create new, unwanted compounds, further reducing the experiment’s accuracy by adding contaminants.

In addition, when the result of the combustion reaction of ethyne is being observed, it is important to ensure any observations, specially the smell and smoke produced, are created by the reaction and not from burning the wooden spit, which also generates smell and smoke, especially when it is extinguished. This can be remedied by extinguishing the spit away from the test tube at a place that is not upwind of the