List of organic compounds for analysis: · Part 3

a copper complex with Cu + ions from copper sulphate solution. This copper –biuret complex is deep violet coloured. NH N H H N biuret NH H N urea (Excess) C -NH Cu + Cu + NH NH H N H N NH NH H N NH NH NH NH H N [Cu(Biuret) ] + complex (violet colour) organic organic - - - - . Molisch’s test: Disaccharides, and polysaccharides are hydrolysed to monosaccharides by strong mineral acids. Pentoses are then dehydrated to furfural, while hexoses are dehydrated to -hydroxymethylfurfural. These aldehydes formed will condense with two molecules of α-Naphthol to form a purple-coloured product, as shown below. HO -(hydroxymethyl) furfural OH α -naphthol H O + HO OH OH HO OH H O + [O] A purple dye + -H O H HO H HO H OH OH H H OH H O + -3H O HO -(hydroxymethyl)furfural .Osazone test: Phenyl hydrazine in acetic acid, when boiled with reducing sugars forms Osazone. The first two carbon atoms are involved in this reaction. The sugars that differ in their configuration on these carbon atoms give the same type of Osazone. Thus glucose, fructose and mannose give the same needle type yellow crystals. C C OH H C H HO C OH H C OH H CH OH H HN H N phenyl hydrazine Glucose C C N C H HO C OH H C OH H CH OH N H NH NH Glucosazone (Yellow crystals) organic organic - - - - . Estimation of Ferrous Sulphate (Fe + ) Aim : To estimate the amount of ferrous sulphate dissolved in ml of the given unknown solution volumetrically. For this you are given with a standard solution of ferrous ammonium sulphate (FAS) of normality . N and potassium permanganate solution as link solution. Principle: During these titrations, Fe + ions (from ferrous salts) are oxidised