Practical organic chemistry carbohydrates Carbohydrate polyhydroxy aldehydes or

Practical organic chemistry carbohydrates

Carbohydrate: - polyhydroxy aldehydes or polyhydroxy ketones Feature of carbohydrate 1) Contain C , H, O (1: 2: 1) 2) Contain asymmetric carbon atom 3)Contain hydroxyl group (OH) 4)Contain carbonyl group

carbohydrate monosaccharide Can not be hydrolyzed to simpler compound Aldose Contain (-CHO) group disaccharide Hydrolyzed to two monosaccharide ketose Contain (C=O) group polysaccharide Hydrolyzed to many monosaccharide molecules

1) Monosaccharide FRUCOSE 2)Disaccharide O

Maltose

3) polysaccharide n

State: - solid Colour: - Physical properties Odour: pleasant solubility: - soluble in cold water except starch Effect on litmus paper: neutral

Test Molish test glucose fructose lactose maltose sucrose starch Violet ring spread by shacking 1 ml alc. alpha naphtol 1 ml of sugar

Test glucose fructose lactose maltose sucrose Effect of heat Melts then char with odour of burnt sugar starch Char without melt with odour of burnt sugar

Test Fehling test glucose fructose lactose maltose Reddish brown ppt sucrose starch -ve 1 ml Fehling (B) 1 ml Fehling (A) 1 ml sugar

Test glucose fructose lactose maltose Silver mirror or grey ppt sucrose starch -ve Heat in water bath 1 ml sugar

Test Iodine test glucose fructose lactose -ve maltose sucrose starch Deep Blue colour 1 ml starch

Test Ozazone glucose fructose Yellow crystals during heating lactose maltose Yellow crystals after heating sucrose starch -ve Heat in water bath for 15 -20 min. 5 ml of water 0. 3 gm of sod. acetate 0. 2 gm of phenylhydrazine. HCl 0. 1 of sugar

Test Barafoid test glucose fructose Red ppt lactose maltose sucrose starch -ve -ve 1 ml barafoid 1 ml Suger

Test Selwanoff test glucose fructose lactose maltose sucrose starch -ve Red ppt -ve -ve 1 ml selwanoff reagent 1 ml fructose

Test furfural test glucose fructose lactose maltose sucrose starch -ve Red colour -ve -ve Direct heat Aniline acetate 3 ml HCl 0. 1 gm of fructose

glucose Molish test Effect of heat Fehling test Iodine test ozazone barafoid Seliwanoff test furural test fructose lactose maltose sucrose starch