Qualitative Analysis Lab

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Qualitative Analysis Lab Report

Organic Chemistry Laboratory II

ABSTRACT: The purpose of this lab was to separate and purify two unknown compounds, one solid and one liquid, from an ethereal solution using the techniques of chemically active extraction, vacuum filtration, simple distillation, and recrystallization. Then identifying information was compiled about these unknowns by obtaining experimental melting/boiling point ranges, and analyzing IR and proton/carbon NMR spectrums It was determined that the unknown solid’s identity was m-nitrobenzoic acid and the unknown liquid’s identity was 4,4-dimethyl-2-pentanone. The calculated percent recovery for the purified crystals was 20.75%
INTRODUCTION: 2 The goal of this lab was to isolate
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Vacuum filtration is able to separate the solid from the liquid. For a diagram of the set up of vacuum filtration see the figure below:
Figure #2: The set up for a vacuum filtration apparatus.5

The liquid unknown can be purified through the technique of simple distillation. Simple distillation is used to purify a compound that is almost pure already. It takes advantage of the fact that liquids have varying boiling points, and in this lab can be used to evaporate off the organic solvent (which has a very low boiling point) that was still in the organic layer with the neutral component, leaving the neutral component by itself. In simple distillation vapor rises from the distillation flask and comes into contact with a thermometer that records its temperature and gives a starting point for the liquids boiling point range. The vapor passes through a condenser, which turns it back into a liquid and it is collected in the receiving flask. To see a diagram of a simple distillation apparatus set up see the figure below:
Figure #3: The set up for a simple distillation apparatus.3

The next techniques in this lab were identification tactics to determine the identities of these purified, unknown compounds. One was already mentioned, which is recording the boiling point range of the unknown liquid. This range can be compared with literature values to confirm the identity of the unknowns once other
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