Question

How Would You Test The Presence Of Starch In Leaves Class 7Th

Answer 1

Answer:

First of all take a piece of green leaf and some iodine solution to it.

If the color of the leaf changes to purple, It will prove that the leaf contains some starch in it.

PLEASE MARK IT AS THE BRAINILIEST

Explanation:

Answer 2

Answer:

Requirements:

Sample plants

Glass jar or beaker

Stove and saucepan

Iodine solution

Ethyl alcohol

Tweezer

Procedure:

Set up one plant on a sunny windowsill and another in a dark room for 24 hours

After 24 hours, fill a beaker with ethyl alcohol and place it in a saucepan full of water

Continue heating the pan until ethyl alcohol starts boiling and then take it off from the heat

With the help of tweezers, dip each of the leaves in hot water for a minute

Now, dip the leaves in the beaker holding ethyl alcohol for 120 seconds or till they change their color to almost white

Place each of them in a shallow dish

Cover these leaves with some drops of iodine solution and observe

Observation:

Alcohol breaks down the chlorophyll and hot water kills the leaf. Hence, the leaf is no more green in color

When leaves are treated with iodine, one of them turns its colour to blue-black due to the presence of starch with iodine as an indicator. The other leaf turns its colour to reddish-brown

The leaf that was kept in light turns blue-black in colour indicating the leaf has been carrying out photosynthesis, producing starch