Student A carried out an experiment to test for the presence of simple sugar in
ID: 277245 • Letter: S
Question
Student A carried out an experiment to test for the presence of simple sugar in a potato. He did the experiment using a chemical indicator called orange when heated in the presence of simple sugars. He had previously verified that the indicator solution was effective by testing it on a known simple sugar, glucose. Benedict's solution, which turns bright To carry out his potoxe, he aded the folowing to his experimental test tube ground up potato distilled water 10 drops of glucose solution 5 ml of Benedict's solution Following a few minutes of heating, the Benedict's solution turned bright orange. The student concluded that potato contains simple sugars. 1. Do you agree with his conclusions? Explain your answer 2. What would be an appropriate control for this experiment? Now raald yocExplanation / Answer
1. The conclusion is not completely wrong as potato contains simple sugars such as glucose and fructose in small quantity in additon to complex sugars.But here the change in benedic reagent is also influenced by 10 drops of glucose in the test tube. Benedict solution only changes colour with simple sugars, not bonded sugars like strarch present in potato. Here the benedicts solution changed colour because in addition to potato the student also used 10 drops of glucose in the test tube. so the significant colour change was due to this glucose molecules ( simple sugars) not only because of potato.
2. An appropriate positive control will be glucose slution and benedics solution, negative control will be distilled water and the test solution needs to have only ground potato with distilled water.