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Organic compound identification.

Extracts from this document...

Introduction

A Level Chemistry Practical ORGANIC COMPOUND IDENTIFICATION The reason to carry out different chemical test on the unknown six organic compounds is to find their structure and identity. The unknown compounds are labeled as compounds A ? F respectively. We are provided with the information that tells us the sort of different chemical tests that have to be performed on the compounds and we are provided with the technique to carry out these chemical tests. We are given the composition of each compound so we know what are the elements that are in the compounds and what ratio are they in. Along with the composition data we are also provided with different sorts of other data that will make our task easier and much more bearable. For e.g. we are provided with Mass spectrum in some cases while having the infrared and NMR spectrum in the other along with other tidbits of information specific to each compound. Along with carrying out the chemical tests and coming up with the identity of the compounds we are also expected to answer different questions about them. Like for example we are asked to write down the chemical equations in some cases of the chemical test that we are carrying out and in some cases the mass concentrations and molarity. I am also provided with Chemical test and Inferences. I have been given two tables and there titles and brief description is as follows: * The first table is titled Solubility in water and pH of resultant solution ...read more.

Middle

3. a) After adding the lithmus solution the suspension went red b) Adding the magnesium and reheating results in a reaction and a gas is given off. c) The yellow/orange color of bromine water goes transparent meaning it decolorized. d) The acidified potassium manganate decolorized as well. Chemical Tests Results 1. The colorless gas that was given off was diagnosed as CO2. This was the, prove for the presence of a carboxylic acid functional group. 2. The white fumes given off after testing the gas with the stopper from the concentrated ammonia bottle told us that the gas given off was HCL and this proved that there was an OH group of a carboxylic acid in the compound. 3. a) The solution to change the color to red meant that the compound is acidic. b) The gas that was given off was hydrogen. c) The decolorizing of the Bromine Water meant that there was an Alkene functional group in the compound. d) The decolorizing of the acidified potassium manganate is prove that there is an acid group in the compound. Identity And Structure The unknown compound B is likely to be Cinnamic Acid. Structure: Compound C Composition: C = 66.6% H = 11.2% hence E.F. = C4H8O O = 22.2% The mass and infra red spectra of compound C was given can be found on the Appendix sheet. The Mr and the molecular formula of C were deduced. The infra red spectrum gave a signal and was identified as: Mr of C = 72 M.F. ...read more.

Conclusion

Structure: Compound F Formula = C3H7X, where 'X' is a halogen atom. Chemical Test Add a few drops of F to 2 cm3 of NaOH solution in a test tube then warm in a water bath for 3 - 4 minutes with occasional shaking. Acidify with about 3 cm3 of dilute nitric acid then add a few drops of silver nitrate solution. Note the appearance of any precipitate then test its solubility in excess dilute ammonia solution. Use your results to identify the halide in F. By using the N.M.R. spectrum provided of Compound F I was able to determine the structure of F. The isomer of F has the N.M.R. spectrum shown. Draw the structure of this isomer and account for the appearance of the spectrum. Write equations for the reaction of Compound F with: (a) Sodium cyanide dissolved in alcohol (b) Alcoholic potassium hydroxide. In each case name the organic product. Chemical Tests Observations In the beginning after adding the NaOH the solution remained clear and transparent. After heating the solution there were two layers that formed. A large lower layer and a smaller upper layer. The upper layer was less dense and a bit less transparent. After acidifying the lower layer turned cloudy and the upper layer remained the same. The solubility of the slightly creamy white precipitate was tested. Chemical Tests Results The conclusion drawn by testing the solubility is that the liquid is not miscible and the color of the precipitate tells us that the Halide X is Chlorine. Identity And Structure The unknown compound F is likely to be Propyl Chloride. Structure: 1 ...read more.

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