the daily dose of the daily dose of the daily dose of the daily dose of 7. Recor
ID: 1044959 • Letter: T
Question
the daily dose of the daily dose of the daily dose of the daily dose of 7. Record observations in the table below. | 1% Sugar/ Starch Glucose Fructose Maltose Lactose Sucrose Starch Benedict's Test Observations lodine Test Observations C. Hydrolysis of Sucrose and Starch 1. Place 10 drops of 1% sucrose solution in one test tube and 10 drops of starch solution 2. 3. 4, in another. Add 5 drops of concentrated hydrochloric acid (HCI) (caution-strong acid) to each. Place the test tubes in a beaker of boiling water for 10 minutes. Stir occasionally. Cool, then add 10% sodium hydroxide (NaOH) solution drop by drop until the solu- tions are alkaline (basic) to litmus paper. (Red litmus turns blue in base.) Record your observations so far Glass stirring rod Litmus paper Drop of solution Describe Solution Sucrose Starch 5. Add 10 drops of Benedict's solution to each test tube. 6. Heat in a boiling water bath for 5 minutes. 7. Observe and record observations. Describe Solution after Benedict's Test Sucrose StarchExplanation / Answer
All monosaccharides are reducing sugars because they have an aldehydic group in case of aldoses.They can also tautomerize in solution to form an aldehyde group in case of ketoses e.g. Glucose and fructose.Those diasaccharides that have reducing form,as one of the two units may have an open chain form with an aldehydic group e.g.lactose and maltose.All these reducing sugars are detected by Benedict's test. Positive Benedict's test is shown by a color change from blue to brick/orange red precipitate.
Iodine test:-It is used for the detection of presence of starch.Formation of deep blue colour solution indicate the presnce of starch.
Sucrose is an non-reducing diasacchrides so give -ve tests in both case.
c) Hydrolysis of sucrose converts sucrose into glucose and fructose.
After adding HCl to the starch solution and heating the test tube for a while there is no change in the solution colour on the addition of iodine.that means there is no starch in the solution,it will contain glucose units because starch is made up of glucose.
After hydrolysis both starch solution and sucrose solution give + ve Benedict's test because now solution have reducing sugar.
1% sugar/starch Benedict's test Iodine test Glucose +ve test -ve test Fructose +ve test -ve test Maltose +ve test -ve test Lactose +ve test -ve test Sucrose -ve test -ve test Starch -ve test +ve testRelated Questions
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