Question

few drop of dilute iodine solution is added to both the text tube blue color appears in the test tube B what change occurs in test A ? why?​

Answer 1

This shows the presence of starch in solution B which might be absent in solution A .

Explanation:

Iodine is a solution which is blue in colour and gives change in colour when added to starch solution .

Hence In B starch is present , so color changes while it was absent in A , Hence no color change occur.

Answer 2

Blue color appears due to the presence of starch.

Explanation:

• Test tube A contains saliva and test tube B contains potato juice.
• When iodine is added to the test tubes the color of test tube B changes into dark Blue color.
• This is due to the presence of starch.
• Iodine test is used to determine the presence of starch in a solution.
• Therefore we can say that solution b contains starch.