Qualitative Analysis of Functional Groups
The experiment seeks to find out the roles the variables such as aldehydes and ketones in determining the classes in which the unknown compounds belong to. Hypothesis The null hypothesis is that an individual organic compound can be categorized on the basis of functional groups that is found in the compound. The tests that will be carried out on every unknown compound will seek to establish the functional groups contained in the compound. This process will guide the identification of the compound. The hypothesis further suggests that the variables are the main determinant of the classification of the unknown compound. Another test tube was taken, placed on a test tube stand and 10 drops of acidified ceric ammonium nitrate solution poured into it.
On the test tube containing the ceric acid solution, three drops of the unknown compound #1 was added and the observations were recorded 7. Steps 5 and 6 above were repeated but now with the remaining four unknown compounds #3, 7, 11 and 15. This was the ceric nitrate test 8. 5 drops of chromic acid were taken, mixed with 5 drops of acetone and poured into another clean test tube. Three drops of the unknown compound #1 were taken and poured into a clean test tube. 20 drops of 5% FeCl3 solution was added into the test tube containing unknown compound #1. The mixture was stirred and the observations were recorded. Steps 14 and 15 above were repeted for unknown compounds #3, 7, 11 and 15. This was the iron chloride test 17. Steps 21 and 22 were repeated for the rest of the unknown compounds #3, 7, 11 and 15.
This was the potassium permanganate test. The station was cleaned after recording all the observations. Observations Unknown compound Water solubility Ceric nitrate Chromic acid DNPH Iron chloride Iodoform Potassium permanganate 1 Bp < 1100 Not soluble negative negative positive negative negative positive -2 layers were formed in water -No red layer formed -The red orange did not disappear -There was formation of orange-red precipitate -A light orange precipitation was formed -No yellow precipitate formed -The purple color of the KMnO4 solution disappears and a precipitate of MnO2 is formed 3 Bp > 1600 Not soluble Negative positive Positive Negative Negative Positive -2 layers were formed in water -No red or red-brown layer formed -The red orange did not disappear -Formation of orange red precipitate -A light orange precipitation was formed -No yellow precipitate formed -The purple color disappeared 7 Bp > 1100 Not soluble Negative Negative Positive Negative Positive Negative -2 layers were formed in water -The yellow layer remained -The red orange layer remained -A yellow precipitate was formed -The yellow layer remained - Yellow precipitate was slightly visible -Solution faded to yellow -Yellow precipitate formed -The purple layer remained 11 Bp > 900 Not soluble Negative Negative Negative Negative Negative Negative -2 layers were formed in water -The yellow layer remained -The red orange layer remained The orange color remained -The yellow layer remained - Yellow precipitate was slightly visible Solution faded to yellow -The purple layer remained 15 Bp < 1100 Soluble Negative Positive Positive Negative Negative Positive -Solution was clear - Compound dissolved in water -The yellow layer remained -A dark blue green layer was formed -A yellow precipitate was formed -The yellow layer remained - Yellow precipitate was slightly visible Solution faded to yellow -The purple color disappeared Results Unknown compound Functional groups and properties Classified organic compound 1 Bp < 1100 -Contains more than 3 Carbons -OH group (alcohol) Methyl aldehydes 3 Bp > 1600 -Contains more than 3 Carbons -contains methyl ketones and acetaldehyde Ketone aldehydes 7 Bp > 1100 -Contains more than 3 Carbons -Carbonyl Group (Aldehyde or Ketone) -Acetaldehyde or methyl ketone Methyl Ketone 11 Bp > 900 -Contains more than 3 Carbons -carbonyl group Alkane 15 Bp < 1100 - Contains less than 6 Carbons -Ethanol and phenyl present Methyl ketones Discussion Function groups in this sector is defined by specific properties that atoms have in a given organic compounds.
The groups are determined through a series of tests along with the study of physical properties of the compound. The rest of the compounds tested negative chromic acid, meaning that they cannot be primary alcohols. The iron chloride tested negative for all the compounds, depicting that the compounds had no alcohol and phenyl groups. Only compound 15 was soluble in water while the rest of the compounds were insoluble. This means that compound 15 must be a primary alcohol because normally, soluble compounds contains less carbon than the insoluble. The other compounds could not be primary alcohols since they were not soluble. This laboratory test had a few errors. However, the errors did not significantly affect the results. The major error occurred because the tests were only carried out once.
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