click below
click below
Normal Size Small Size show me how
chemistry lab
identification of organic compounds
how to prepare the neutral solution? | dissolve a small quantity of the sample in distilled water. put drops of ammonia till you are able to smell ammonia and test the solution using red litmus paper. heat the solution using a porcelain basin till the vapours do not smell ammonia. and again d |
how to identify oxalic acid ? | dissolve a small quantity of compound in distilled water and add sodium bicarbonate solution to it . immediate effervescence indicates the presences of acidic group.(-COOH group) in oxalic acid. |
how to confirm oxalic acid? | to a little of the neutral solution of the compound , add acetic acid and CaCl2 solution. A white precipitate of calcium oxalate will be formed. |
how to confirm tartaric acid? | to a little of the neutral solution of the compound, add equal quantity of tollen's reagent( Ammniacal Silver nitrate). Appearance of metallic silver on the test tube will be the observation. the =CHOH group in tartaric acid |
how to succinic acid? | In a dry test tube take small amount of the compound and 1-2 crystal of resorcinol; add 2-3 drops of conc H2SOR4. heat the mixture till it becomes reddish brown. add drop of this into about 50 ml of tap water, taken in a small beaker and add 2-3 ml of NaO |
how to do the molisch's test? | This is an identification test for all carbohydrates indicating the presence of poly hydroxyl group in carbohydrates. all carbohydrates will answer this test. To an aqueous solution of the compound add two drops of 10% alcoholic solution of alpha naphthol |
how to do the fehling's test? | (distinction of reducing and non reducing sugar)-glucose and fructose will answer to this test while sucrose and starch will not. To an aqueous solution of the solid add few drops of fehlings solution and heat by keeping it in water bath for a minute. A r |