Few drop of dilute iodine solution is added to both the test tubes blue colour appear in the test tube B what changes occur in a test tube A why few drops of dilute Iodine in solution is added to both the test tube test tube
Answers
Test tube B contained starch because of which blue black color appeared but in test tube A no starch was present so no reaction occurred.
Hope it is helpful.
Answer with respect to iodine is given below-
In the two test tubes in question, B must be the one containing starch while A either does not contain starch or it contains starch degrading amylase enzyme.
Reaction which gives blue colour has interaction between starch molecules and iodide ions giving starch iodide complex. This reaction occurs in test tube B.
In test tube A, the first case will have no reaction, while in second case, amylase enzyme breaks starch into it's monomeric unit namely maltose.
Hence, absence of starch does not give dark blue colour.
Iodine test is generally used to check presence of starch.