“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.