Obtaining aldehydes by oxidation of alcohols. They say that if you heat a test tube with methyl alcohol

Obtaining aldehydes by oxidation of alcohols. They say that if you heat a test tube with methyl alcohol and potassium permanganate, then, as formaldehyde is formed, the purple color of the solution will disappear. Why?

When heated, potassium permanganate decomposes with the release of oxygen, which oxidizes methanol. This produces formaldehyde and water. The purple color of the solution is due to the presence of potassium permanganate KMnO4 (more precisely, MnO4- ions). The decomposition of potassium permanganate produces potassium manganate (K2MnO4), manganese oxide and oxygen. Ions MnO4 / 2 – do not color the solution in violet. Those. the number of ions that colored the solution is reduced, therefore the color disappears.