When performing a scientific investigation on an unknown substance how can an indicator help you determine if the substance is starch
An indicator can help determine if a substance is starch by changing color in the presence of starch. There are specific indicators that react with starch and produce a color change. One common indicator for starch is iodine solution.
To identify if a substance contains starch using an indicator:
1. Take a small amount of the unknown substance.
2. Place the sample in a test tube or a petri dish.
3. Add a few drops of iodine solution to the sample.
4. Observe any color changes that occur.
If the substance contains starch:
- It will turn from its original color to a dark blue or black color in the presence of iodine solution.
- The color change occurs due to the formation of a complex between iodine and starch molecules.
If the substance does not contain starch:
- There will be no color change or any noticeable reaction with the iodine solution.
- The sample will retain its original color.
By using an indicator like iodine solution, scientists can quickly and easily determine the presence or absence of starch in an unknown substance.