Aim: to test the presence of carbohydrate in given sample
Materials Required: Test tube, test tube holder, sugar solution, Benedict's solution, spirit lamp.
Principle: Sugar contain aldehyde and keto-group which readily reduce metallic oxides, specially cupric to cuprous oxide. In Benedict's solution CuSO4 is mixed with sodium citrate and sodium carbonate (Na2CO3) which is more stable. In Alkaline Solution all Reducing sugars, glucose, fructose and lactose precipitate Cu2O. In acidic solution only the polysaccharides reduce cupric salt.
observation table
Result: The solution resulted in yellow precipitate formation in sample A, hence carbohydrate is present in sample A
Materials Required: Test tube, test tube holder, sugar solution, Benedict's solution, spirit lamp.
Principle: Sugar contain aldehyde and keto-group which readily reduce metallic oxides, specially cupric to cuprous oxide. In Benedict's solution CuSO4 is mixed with sodium citrate and sodium carbonate (Na2CO3) which is more stable. In Alkaline Solution all Reducing sugars, glucose, fructose and lactose precipitate Cu2O. In acidic solution only the polysaccharides reduce cupric salt.
observation table
Experiment
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Observation
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Inference
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Clean test tube was taken and 5 ml of Benedict’s reagent was taken in it, 3-4 drops of sample A was added to it, the mixture was thoroughly heated on spirit lamp or boiling water bath
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Red or yellow of Cu2O was formed
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The given solution contains sugar monosaccharide and reducing disaccharides
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Clean test tube was taken and 5 ml of Benedict’s reagent was taken in it, 3-4 drops of sample B was added to it, the mixture was thoroughly heated on spirit lamp or boiling water bath
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Yellow ppt not formed
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_____
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Result: The solution resulted in yellow precipitate formation in sample A, hence carbohydrate is present in sample A
