Question

Starch turns ____ colour from purple to bluish black

Answer 1

Answer:

iodine

Explanation:

This is called iodine test.To find the presence of starch we add iodine to the material.Iodine present in the aqueous pottasium iodide solution gets entangled in the starch and form starch iodine complex.Hence starch turns blue black

• Hope this may help u

Answer 2

Answer:

iodine

Explanation:

Iodine - KI Reagent: Iodine is not very soluble in water, therefore the iodine reagent is made by dissolving iodine in water in the presence of potassium iodide. This makes a linear triiodide ion complex with is soluble that slips into the coil of the starch causing an intense blue-black color.