the mixture turns black
yeee
If you mean to test for starch then Iodine
Blue or Purple
No, it is physical
Blue color
some kind of chemical reaction
This mixing is not a chemical reaction.
You can test for starch in general using the chemical iodine test. If starch is present, a solution of iodine (I2) turns blue-black.
Iodine reacts with starch, but not with talc, to produce a blue color.
The color would be a yellowish-orange.
Powdered Sugar
Crisps are made from potatoes which are very high in starch. When iodine is added to starch it forms a complex with it and results in a purplish color. you get the same thing if you put an iodine sol'n on bread or cornstarch.