A positive test result for starch occurs when the substance in question causes a solution of iodine to turn a deep blue or purple-black color. The iodine retains its usual yellowish color when no starch is present. More » Science Chemistry Solutions & Mixtures

The test that is usually used to identify the presence of starch in a sample is the iodine test. One of the two components of starch, specifically amylose, reacts to iodine, generating a deep blue color. Although the pre... More » Science Measurements

The purpose of boiling a leaf before testing it for starch is to stop any more reactions from occurring in the leaf. If the processes inside the leaf are not stopped, then the starch could be used and not be picked up in... More » Science Chemistry
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Iodine solution is made by mixing iodine into a mixture of potassium iodide; this mixture is commonly used to check for starch. Iodine solution is also known as povidone and is used to kill bacteria and treat infections ... More » Science Chemistry Solutions & Mixtures

In a solution, iodine ions indicate the presence of starch by changing the color of the solution from yellow to intense blue. Iodine ions are typically added to a solution as potassium iodide. More » Science Chemistry

A hypoidite anion is a very unstable, negatively charged ion that is created when an aqueous solution of iodine is treated with mercuric or silver salts. The substance that results from the reaction also is known as hypo... More » Science Chemistry Solutions & Mixtures

Iodine solution turns blue-black when mixed with any substance containing starch, such as potato, bread, crackers and flour. When iodine reacts with starch, it is trapped in the starch's helical structure forming a blue-... More » Science Chemistry Solutions & Mixtures