The bright colors of anodized aluminum are due to:a. electrodeposition of organic dyes on the aluminum surface. b.the formation of an aluminum alloy with chromium and copper. c. iridescence involving the semitransparent outer layer of aluminum oxide. d. trapping of organic dye molecules in a spongy aluminum oxide matrix.
Answer is D, trapping of organic dye molecules in a a spongy aluminum oxide matrix. Although I don't know who wrote these answers; anodizing aluminum is also done to make it harder. See the site below. Good luck!
