Question

Lab question

Table 5A-1 Data Table for Benedict's and Lugol's Tests Benedict's Test Lugol's Test Origia Final Color Color Before Boiling Tube After After 1. Water 2. Starch 3. Glucose elue owrm 5. Sucrose 6. Onion juiceGen Crenve 7. Potato slice l ecue | Green | WhLte一一1tra-areen 8. Milk Did the results for each test support your hypotheses? Did your results support your null hypothesis? Did the results for cach test agree with your predictions? Explain any discrepancies. PART 2-LUGOL'S TEST FOR STARCH Lugol's reagent changes from a brownish or yellowish color to blue-black when or disaccharides. Formulate a hypothesis and predict what you might expect to find for each of the sugars to be tested with Lugol's reagent (Table 5A-1). starch is present, but there is no color change in the presence of monosaccharides Hypothesis Prediction 1. Water 2. Starch 3. Glucose 4. Maltose 5. Sucrose 6. Onion juice 7. Potato slice 8. Milk What is your null hypothesis for this group of tests? What is the independent variable? What is the dependent variable?

Answer 1

Null Hypothesis: No color change in the test is observed if monosaccharide or disaccharide is present in the sample.

Independent Variable: Presence or absence of monosaccharide or disaccharide in the sample.

Dependent Variable: Change or no change in color on addition of test reagents.

                                                            

	Hypothesis	Prediction
Water	No monosaccharide or disaccharide present hence color change   should be observed	A color change should be observed on addition of test reagents
Starch	Color should change due to the presence of starch	Color changes from brownish or yellowish to blue-black
Glucose	Mono or disaccharide present hence no color change should be observed	No color change should be observed
Maltose	Mono or disaccharide present hence no color change should be observed	No color change should be observed
Sucrose	Mono or disaccharide present hence no color change should be observed	No color change should be observed
Onion Juice	No monosaccharide or disaccharide present hence color change   should be observed	A color change should be observed on addition of test reagents
Potato Slice	Color should change due to the presence of starch	Color changes from brownish or yellowish to blue-black
Milk	Mono or disaccharide present hence no color change should be observed	No color change should be observed

                                                 

Answers to questions based on Table 5A-1 Results

Answer 1: Not all the results supported the hypothesis. For example-In case of potato slice (which contains starch), a blue-black color should have been observed at the end of the test.

Answer 2: Not all the results supported the null hypothesis. For example- In case of sucrose (which contains disaccharide), no change in color should have been observed in the test.

Answer 3: Not all the results agreed with the predictions. For example – In case of onion juice (which does not contain any mono or disaccharide), a color change should have been observed.

Answer 4: Please quote the above discrepancies. You can also mention other test results based on your observations.

Thanks!