the mixture turns black
Mixing iodine with cornstarch does not result in a chemical reaction. Instead, it forms a physical mixture in which the iodine molecules become trapped within the starch molecules, causing the mixture to change color. The iodine acts as an indicator of the presence of starch.
When iodine is added to cornstarch, a blue-black complex is formed. This is utilized as a simple test to detect the presence of starch in a given substance.
No, mixing cornstarch with water is not a chemical reaction. It is a physical change. The cornstarch particles disperse throughout the water, but no new substances are formed.
Blue or Purple
If you mean to test for starch then Iodine
One way to test if a powder is talc or cornstarch is by performing a iodine test. Mix the powder with iodine solution; if the mixture turns blue-black, it is likely cornstarch. Another way is to do a simple solubility test: dissolve the powder in water and if it is talc, it will not dissolve and settle to the bottom, while cornstarch will dissolve.
Blue color
Oh, dude, mixing cornstarch and water is a physical change. You're just creating a mixture, not changing the actual molecules of the cornstarch or water. It's like when you mix chocolate syrup into milk - it's still just chocolate milk, not a crazy science experiment.
Iodine does not react with baby powder. Baby powder is usually made of talc or cornstarch, which are inert substances and do not participate in chemical reactions with iodine.
When mixing iodine with hexane, the resulting color will be purple or violet. This occurs because the iodine molecules dissolve in the hexane, resulting in a purple solution.
You can test for starch in general using the chemical iodine test. If starch is present, a solution of iodine (I2) turns blue-black.
When cornstarch is mixed with iodine, a process called iodine starch complex formation occurs. This reaction turns the mixture dark purple because the iodine molecules interact with the starch molecules and form a specific type of complex that absorbs light in the visible spectrum, giving it a purple color.