Boojho took some grains of boiled rice in a test tube ‘A’, and Paheli took boiled and chewed rice in a test tube ‘B’. Both of them poured 1 – 2 drops of iodine solution into the test tube and observed the colour change. What colour change would they have observed? Give reasons for your answer.
ScienceClass 7CBSEAnswered 27 Mar 2026
Answer
Soln:
In test-tube A colour of iodine changes to blue-black because of the reaction of iodine with starch. In test-tube B colour will not change because salivary amylase acts on starch while chewing, reducing it to simpler sugars.
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