Question

Which chemical is used to test for starch?which colour shows the presence of starch?

Answer 1

Answer:

Iodine is the chemical which is used to test starch.

It is colour change to blue indicates the presence of starch.

Answer 2

The chemical used to test for starch is Betadine/Iodine solution.Starch is often used in chemistry as an indicator for redox titrations where triiodide is present. Starch forms a very dark blue-black complex with triiodide which can be made by mixing iodine with iodide (often from potassium iodide).

What is the procedure for the iodine test for starch?

The procedure for the iodine test for starch depends on whether the test sample is a solid or liquid.

The procedure for the iodine test for starch depends on whether the test sample is a solid or liquid.SOLID SAMPLE:

1. Peel off the skin of any vegetables e.g. potato and fruits as these are often impermeable. Use a clean spatula to remove samples of powdered food. Avoid cross contamination with other foods.
2. Peel off the skin of any vegetables e.g. potato and fruits as these are often impermeable. Use a clean spatula to remove samples of powdered food. Avoid cross contamination with other foods.Add a few ( 2-3) drops of bench iodine solution potassium to a piece of solid food on a white tile.
3. Peel off the skin of any vegetables e.g. potato and fruits as these are often impermeable. Use a clean spatula to remove samples of powdered food. Avoid cross contamination with other foods.Add a few ( 2-3) drops of bench iodine solution potassium to a piece of solid food on a white tile.Make observations.

LIQUID SAMPLE:

1. Add 10 cm3 of the liquid food sample to a clean, dry test tube.
2. Add 10 cm3 of the liquid food sample to a clean, dry test tube.Add about 5 drops of iodine solution to the test tube.
3. Add 10 cm3 of the liquid food sample to a clean, dry test tube.Add about 5 drops of iodine solution to the test tube.Note any colour changes.
4. Add 10 cm3 of the liquid food sample to a clean, dry test tube.Add about 5 drops of iodine solution to the test tube.Note any colour changes.To prepare a control, perform steps 1 -3 for de-ionized water.

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