Experiment 11 - Nermine Choumane Ahmad El Zein

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Nermine Choumane Ahmad El Zein Experiment 11 :   Test for Organic Chemical                                     compounds 1 - Tollen’s Test for Aldehydes Ag + ions react with OH - of aqueous ammonia to produce a brown precipitate of AgOH which is dissolved on addition of an excess of aqueous ammonia under the formation of [Ag(NH 3 ) 2 ] + . Fig. 1: Redox reaction The Tollens' test is important in carbohydrate chemistry, for proof of structure. The test is specific for reducing sugars. Fructose is also capable of reducing Tollens' solution, and is thus classified a "reducing sugar".
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Nermine Choumane Ahmad El Zein 2 - Jones Oxidation for Primary and Secondary Alcohols The most generally useful reagents for oxidizing 1º and 2º-alcohols are chromic acid derivatives. Two such oxidants are Jones reagent (a solution of sodium dichromate in aqueous sulfuric acid) and pyridinium chlorochromate, C 5 H 5 NH (+) CrO 3 Cl (–) , commonly named by the acronym PCC and used in methylene chloride solution. In each case a chromate ester of the alcohol substrate is believed to be an intermediate, which undergoes an E2-like elimination to the carbonyl product. Since chromate reagents are a dark orange-red color (VI oxidation state) and chromium III compounds are normally green, the progress of these oxidations is easily observed. A positive test for primary or secondary alcohols consists in the production of an opaque suspension with a green to blue color. Tertiary alcohols give no visible reaction within 2 sec, the solution remaining orange in color.
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Nermine Choumane Ahmad El Zein 3 – Tests for Unsaturation A) – Bromine Test For Multiple Bonds Two common types of unsaturated compounds are alkenes and alkynes, characterized by the carbon-carbon double and triple bond, respectively, as the functional group.
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This note was uploaded on 11/22/2009 for the course CHEMISTRY 300 taught by Professor Dr.valentina during the Spring '09 term at Lebanese International University.

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Experiment 11 - Nermine Choumane Ahmad El Zein

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