nucleophiles and electrophiles Presence of C=O TEST FOR ALDEHYDES AND KETONES - - Reaction with 2‚4-DNP (Dinitrophenylhydrazine) Positive: Formation of yellow precipitate IODOFORM TEST - Carbonyl compounds: Methyl ketones will give a positive result Postive: Yellow precipitate (CHI3) MOLISCH’S TEST for carbohydrates - TOLLEN’S TEST – for aldehydes - - Test for easily oxidizable compounds (ex. Aldehydes) Positive: Silver mirror deposit - - Polyhydroxyaldehydes
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CHAPTER ONE 1.0 INTRODUCTION Starch is one of the most abundant substances in nature‚ a renewable and almost unlimited resource. Starch is produced from grain or root crops. It is mainly used as food‚ but is also readily converted chemically‚ physically and biologically into many useful products to date; starch is used to produce such diverse products as food‚ paper‚ textiles‚ adhesives‚ beverages; confectioning‚ pharmaceuticals‚ and building materials. Cassava starch has many remarkable characteristics
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concentrated sulphuric acid and heat: Fragrant fruity smell of ester liberated CH3COOH + C2H5OH → CH3COOC2H5 + H2O Appendix Ace Ahead Chem (Appendix) 3rd (11/11/08).indd 1 1 11/13/08 12:36:33 PM Homologous series/ Typical compound Aldehydes CH3CHO ethanal Functional group(s) H ⏐ –C=O Chemical tests/Observations (a) Add 2‚4-dinitrophenylhydrazine at room
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SUMMARY OF ORGANIC REACTIONS SECTION 1 - ALIPHATIC Aldehydes and ketones |Type of reaction |Mechanism | |1. oxidation (aldehydes only): aldehyde ( carboxylic acid |n/a | | | | |reagents: potassium
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the development of color are described by the following five mechanistic steps: alpha-amino acid + ninhydrin ---> reduced ninhydrin + alpha-amino acid + H2O alpha-amino acid + H2O ---> alpha-keto acid +NH3 alpha-keto acid + NH3 ---> aldehyde + CO2 Step (1) is an oxidative deamination reaction that removes two hydrogen from the alpha-amino acid to yield an alpha-imino acid. Simultaneously‚ the original ninhydrin is reduced and loses an oxygen atom with the formation of a water molecule
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tests were carried out on butanol‚ butanone‚ unknown a and unknown b which could all be concluded as positives tests given the large amount of yellow to red that formed. This test is therefore one of reliability as it indicates immediately whether aldehydes and ketones are
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QUALITATIVE TESTS OF CARBOHYDRATES Final Lab Report Submitted by Brittany Fitzgerald 545301 Prepared for Nancy Cook Chemistry 3501 Monday November 26‚ 2012 RESULTS PART A: As a result of the Benedict’s test on various sugar solutions‚ it was found that galactose‚ mannose‚ arabinose‚ ribose‚ lactose‚ fructose‚ maltose‚ and cellobiose tested positively and therefore are considered reducing sugars. Glucose‚ starch‚ sucrose‚ and methyl-D-glucopyranoside on the other hand tested
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Fischer Esterification – nucleophilic substitution reaction Strong acid catalyst (concentrated sulfuric acid Purpose of a reflux is to heat a reaction mixture at its boiling temperature to form products‚ without losing any of the compounds in the reaction flask TO HAVE GREAT PERCENT YIELD: As reaction is reversible‚ removal of water or the addition of an excess of one of the reactants (cheaper one) drives the reaction towards formation of ester. (Excess carboxylic acid is used) Adding excess
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Introduction In a Grignard reaction‚ a Grignard reagent (R–MgX) adds to the carbonyl group in an aldehyde or ketone to form an alcohol (Figure 1). The reaction of a Grignard reagent with formaldehyde can be to synthesize a primary alcohol‚ with any other aldehyde can be used to synthesize a secondary alcohol‚ while the reaction with ketone is useful in the synthesis of a tertiary alcohol. Figure 1. General reaction mechanism of a Grignard Reaction The preparation of the Grignard reagent involves
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Experiment 9 Thin Layer Chromatography Experiment: 9 Title: Thin Layer Chromatography Introduction: Chemical analysis is conducted on specific analytes (specific substance of interest in a mixture)‚ however it is often found that these analytes must be separated for the chemical analysis to conduct their analysis. Chromatography is a set up of laboratory a technique that is used to separate a chemical mixture. This technique is very useful as it allows us to follow the course of
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