The aim behind Moll’s half leaf experiment was-
a. CO2
is produced during anaerobic respiration
b. CO2
is produced during aerobic respiration
c. CO2
is necessary for photosynthesis
d. Chlorophyll is necessary for photosynthesis

The correct answer is d. Chlorophyll is necessary for photosynthesis.
Moll’s Half Leaf Experiment was designed to demonstrate the necessity of chlorophyll for the process of photosynthesis. The experiment specifically focused on showing that chlorophyll is essential for photosynthesis to occur, and it involved the use of a leaf from a plant.
The Experiment:
1. Preparation:
o A leaf from a plant (usually a broadleaf like a variegated leaf) was chosen. The leaf was typically from a plant with both green (containing chlorophyll) and non-green (lacking chlorophyll) areas.
o The leaf was then boiled to kill the cells, making it easier to test for starch presence.
o After boiling, the leaf was placed in alcohol (usually ethanol) and heated again to remove the chlorophyll and soften the leaf.
2. Exposing to Sunlight:
o Half of the leaf was exposed to sunlight, while the other half was covered with opaque paper to block the light. The light-exposed area was the one containing the green portion, and the shaded area had non-green tissue.
3. Testing for Starch:
o After the leaf had been exposed to light for a while, it was removed from the alcohol and placed in an iodine solution. Iodine stains starch blue-black.
o The green (light-exposed) area of the leaf turned blue-black, indicating the presence of starch. In contrast, the non-green (shaded) area did not show the blue-black color, indicating no starch was present.
Conclusion:
• The green area of the leaf, which contains chlorophyll, was capable of photosynthesis and produced starch, which was tested by iodine. The non-green area, lacking chlorophyll, could not perform photosynthesis and therefore did not produce starch.
• This demonstrated that chlorophyll is necessary for photosynthesis, as it is the pigment responsible for absorbing light energy, which is used in the photosynthetic process to synthesize glucose.
Why the other options are incorrect:
1. CO2 is produced during anaerobic respiration (a):
o This is incorrect because anaerobic respiration (which occurs in the absence of oxygen) produces ethanol or lactic acid, not CO2. The aim of Moll's experiment was not to demonstrate CO2 production during respiration.
2. CO2 is produced during aerobic respiration (b):
o While CO2 is produced during aerobic respiration, Moll's experiment was not related to respiration but to photosynthesis, particularly the necessity of chlorophyll in the photosynthetic process.
3. CO2 is necessary for photosynthesis (c):
o While CO2 is indeed necessary for photosynthesis, Moll's experiment specifically aimed to show the importance of chlorophyll for photosynthesis, not the role of CO2.
Moll's half leaf experiment aimed to demonstrate that chlorophyll is necessary for photosynthesis. The experiment showed that only the green portions of the leaf (containing chlorophyll) could carry out photosynthesis and produce starch when exposed to light.
Therefore, the correct answer is d. Chlorophyll is necessary for photosynthesis.