investigation for an unknown substance
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“Investigation for an unknown substance”
An Investigational Project for the Partial Fulfillment of Requirements in Organic
Chemistry
Submitted by: Daniel Thomas A. BerberabeBSP-2A
Centro Escolar University
Submitted to: Mrs. Gliceria Masicap
Abstract of Study
The Study is intended for the identification of an unknown substance which is provided by the instructor. The purpose of the study is to
apply different tests and methods learned from Organic Chemistry 11 in detecting the functional group and compositions of unknown
substances provided.
Based on physical tests,The unknown substance provided by the instructor was a colorless
liquid with a characteristic sweet odor. It is highly volatile and flammable. Care must be exercised in handling the substance due to possible fire hazards. The first physical test used is the ignition test
which confirmed that the substance is highly flammable. The odor was tested using the wafting method to determine the characteristic
odor of the substance (Wafting method is important so that mild irritations associated with chemicals can be avoided). Solubility of the substance was tested in Ethyl Alcohol, Acetone and water. The substance was insoluble in water and soluble in both Ethyl Alcohol
and Acetone. The last physical test is the test for Boiling point. The test for the boiling point was done three times yielding an average of
78 degrees Celsius.
Based on the results of the physical tests, the unknown substance exhibits properties similar to an ester. The odor of the substance also
resembles an acetate group because of its similarities with paint, lacquers and plastic balloon odors. To validate the theory of the
compound being an ester, hydroxamic test for esters is employed. The hydroxamic test for the unknown substance provided positive
results and confirmed that the substance is an ester. To further recognize the specific composition of the ester, the physical tests were linked with some examples of acetate groups widely used in
paints, lacquers and plastic balloons. The final result confirmed that the unknown substance was ETHYL ACETATE
METHODOLOGY AND RESULTS
Physical Tests
1. Ignition test
A small amount of substance (preferably 1 drop) is put into a watch glass. The substance is Ignited using a lighted matchstick. The substance burned with a yellow flame.
2. Wafting method (odor test)
The compound is held near the 4. Boiling point
Nose avoiding direct contact and slowly wafting so that the odor can be easily detected. The substancecontains a sweet odor similar to paints, lacquers and plastic balloon.
3. Solubility
The solubility of the substance is tested with Ethyl Alcohol, Acetone and Water. 1 ml of the unknownsubstance is dissolved in 3ml of each compounds.
Water SLIGHTLY SOLUBLE
Acetone SOLUBLE
Ethyl AlcoholSOLUBLE
AVERAGE- 78 degrees celsius
1st TRIAL 80 degreesCelsius
2nd TRIAL 77 degrees Celsius
3rd TRIAL 78 degree Celsius
Chemical Test
1. Hydroxamic test for esters
a.) Preliminary test
1 drop of the unknown substance isdissolved in 1ml of 95% ethyl alcohol and 1ml of 1N HCl. By adding 1 dropof 5% FeCl3,the substance will produce a yellow color.
b.) Final test
1 drop of the unknown substance is Mixed with 1ml of hydroxylamine HClSaturated alcoholic solution and adding 0.2ml of 6N NaOH. The mixture is Heated in a water bath. The mixtureIs cooled slightly after heating. By adding2ml of IN HCl and 5% ferric chloride, aMagenta or burgundy color is produced
The magenta or burgundy color producedCompared to the yellow color of the Preliminary test is a positive result. TheUnknown substance is an ester
ANALYSIS AND CONCLUSION
The unknown substance’s physical characteristics are the key element in determining the composition of the compound. The
chemical test however is vital to prove that the unknown substance is an ester. Esters with low molar mass and derived from carboxylic acids are generally flammable that is why the compound ETHYL
ACETATE is positive in the ignition test because ethyl acetate is a low molar mass ester and it is also derived from acetic acid and
ethanol. One of the main characteristics of ethyl acetate is its sweet odor similar to plastic balloons, this sweet odor is present if the ester
has lower molar mass.
Solubility is also a good test for determining an unknown compound. Ethyl acetate is slightly soluble in water and soluble in ethanol and
acetone. Ethyl acetate is slightly soluble in water because of absence of –OH group and an increase in carbon chain length. Boiling point is the test that specifically identifies the unknown compound because
the acetate groups have definite boiling points. Based on the experimental result, the unknown substance yield an average 78
degree Celsius boiling point close to the theoretical boiling point of ethyl acetate.
The hydroxamic test for ester is a chemical test used to prove that the unknown substance is an ester. The test is used when an ester is reacted with a hydroxylamine hydrochloride saturated alcoholic solution to and then reacting with ferric chloride to form a ferric
hydroxamate which is an indicator that an ester is present.
These evidences lead to the conclusion that the unknown substance is ethyl acetate because of the solid evidences provided by physical
tests such as boiling point, solubility and the hydroxamic test.