Which of the following statement is / are incorrect ?
(i) Green light falling in the range of wavelength 500 -580 nm is least effective for photosynthesis.
(ii) In non - cyclic photophosphorylation, the electron expelled from the reaction centre is not cycled back , though its loos is compensated by electrons from the photolysis of water .
(iii) Chl a , Chl b , carotenoids , and xanthophylls are insoluble in organic solvents.
(iv) 400-700 nm light is used in photosynthesis also known as PAR.
(v) Red light is the most effective for photosynthesis.

Options

A. (iv) and (v)
B. (iii) and (v)
C. (ii) and (v)
D. (iv) only

Answer

To determine which statements are incorrect regarding photosynthesis, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement (i)**: "Green light falling in the range of wavelength 500 -580 nm is least effective for photosynthesis."
- **Analysis**: This statement is **true**. Green light is indeed less effective for photosynthesis compared to red and blue light. Plants primarily absorb red and blue light, while green light is mostly reflected.

2. **Statement (ii)**: "In non-cyclic photophosphorylation, the electron expelled from the reaction centre is not cycled back, though its loss is compensated by electrons from the photolysis of water."
- **Analysis**: This statement is also **true**. In non-cyclic photophosphorylation, electrons do not cycle back to the reaction center; instead, they are replaced by electrons derived from the photolysis of water.

3. **Statement (iii)**: "Chl a, Chl b, carotenoids, and xanthophylls are insoluble in organic solvents."
- **Analysis**: This statement is **false**. While chlorophyll a and b and xanthophylls are generally insoluble in organic solvents, carotenoids are soluble in organic solvents. Therefore, this statement is incorrect.

4. **Statement (iv)**: "400-700 nm light is used in photosynthesis also known as PAR."
- **Analysis**: This statement is **true**. The range of 400-700 nm is indeed referred to as Photosynthetically Active Radiation (PAR), which is utilized by plants for photosynthesis.

5. **Statement (v)**: "Red light is the most effective for photosynthesis."
- **Analysis**: This statement is **false**. While red light is effective, blue light is actually the most effective for photosynthesis. Therefore, this statement is incorrect.

### Conclusion:
The incorrect statements are:
- Statement (iii): "Chl a, Chl b, carotenoids, and xanthophylls are insoluble in organic solvents."
- Statement (v): "Red light is the most effective for photosynthesis."

Thus, the answer is that statements (iii) and (v) are incorrect.