Which indicator is used to check for the presence or absence of simple sugars?

What indcates the presence of simple sugars in a solution?

What indicator is used to check for the presence of starch?
What indicates the presence of starch in a solution?

Here are two sites. The first one describes the test with Benedict's solution for simple sugars. The second one describes the iodine test for starch.

http://www.sciencecompany.com/sci-exper/food_chemistry.htm

http://www.elmhurst.edu/~chm/vchembook/548starchiodine.html

The indicator used to check for the presence or absence of simple sugars is called Benedict's reagent. To use Benedict's reagent, you can follow these steps:

1. Prepare a test solution by adding a small amount of the substance you want to test into a test tube.
2. Add an equal volume of Benedict's reagent to the test tube containing the solution.
3. Heat the mixture gently in a water bath or a Bunsen burner flame for a few minutes.
4. Observe the color change in the solution. If the solution turns green, yellow, orange, or red, it indicates the presence of simple sugars. The intensity of the color change is proportional to the concentration of simple sugars present.

On the other hand, the indicator used to check for the presence of starch is called iodine solution (also known as Lugol's solution). To test for the presence of starch, you can follow these steps:

1. Prepare a test solution by adding a small amount of the substance you want to test into a test tube.
2. Add a few drops of iodine solution to the test tube containing the solution.
3. Observe the color change in the solution. If the solution turns blue-black or a dark purple, it indicates the presence of starch. If there is no color change, it indicates the absence of starch.

Remember, these indicators are specific for the presence of simple sugars (Benedict's reagent) and starch (iodine solution) and may not show positive results for other types of carbohydrates or substances.