Question

Four test tubes were marked as A,B,C and D . Test tube A had salt, B had sugar ,C had chalk powder and D had sago powder . On adding two drops of iodine solution to the content of each test tube , the one that will turn blue-black will be (a) A , (b) B , (c) C , (d) D

Answer 1

test tube D shows blue black colour.
Reason-iodine turns starch solution to blue black. Sago powder contains starch.

Answer 2

D test tube turns into blue black. Because iodine turns starch into blue black colour