To test a leaf for starch, the leaf is boiled in water to (i) ______.
It is then boiled in Methylated spirit to (ii) _.
The leaf is dipped in warm water to soften it. It is places in a petri dish, and (iii) __ solution is added.
The region of the leaf which contains starch, turns (iv) _ and the region which does not contain starch turns (v) _______.

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Solution

Ans. (i) to kill the cells
Concept Explanation:- Boiling the leaf in water will kill the cells present in leaf.
(ii) remove chlorophyll
Concept Explanation:- Boiling the dead leaf in methylated spirit will remove the chlorophyll.
(iii) iodine
Concept Explanation:- Iodine solution is added in order to test presence of starch in leaf.
(iv) blue-black
Concept Explanation:- In leaf, wherever starch is present, that area will turn blue- black in colour and hence, it will prove the presence of starch. The reason behind this is that iodine reacts with starch to form blue-black colour.
(v) brown
Concept Explanation:- The area of the leaf which has no starch won't react with the leaf and therefore, there will no blue-black colour and that part of the leaf will turn brown in colour.
Final answer: To test a leaf for starch, the leaf is boiled in water to to kill the cells. It is then boiled in Methylated spirit to remove chlorophyll. The leaf is dipped in warm water to soften it. It is places in a petri dish, and iodine solution is added. The region of the leaf which contains starch, turns blue-black and the region which does not contain starch turns brown.

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