Chlorophyll a and b are both types of pigments found in plants and algae that are responsible for capturing light energy during photosynthesis. While both chlorophyll a and b play important roles in this process, there are some differences between them.

The false statement regarding chlorophyll a and b is option D, which states that both chlorophyll a and b are present in equal proportion. In reality, chlorophyll a is more abundant in most plants and algae compared to chlorophyll b.

Here is a detailed explanation of each option:

a) Chlorophyll b is an accessory pigment:
- This statement is true. Chlorophyll b is considered an accessory pigment because it assists chlorophyll a in capturing light energy. It broadens the absorption spectrum of plants, allowing them to utilize a wider range of light wavelengths for photosynthesis.

b) Chlorophyll is the main chief pigment:
- This statement is also true. Chlorophyll a is the primary pigment involved in photosynthesis and is the most essential pigment in the process. It absorbs light most efficiently in the blue and red regions of the electromagnetic spectrum.

c) Chlorophyll a is more than chlorophyll b:
- This statement is true. Chlorophyll a is generally present in higher amounts compared to chlorophyll b in most plants and algae. Chlorophyll a is directly involved in converting light energy into chemical energy during photosynthesis, while chlorophyll b functions as an accessory pigment that transfers absorbed light energy to chlorophyll a.

d) Both are present in equal proportion:
- This statement is false. Chlorophyll a is more abundant than chlorophyll b in most plants and algae. The ratio of chlorophyll a to chlorophyll b varies among species, but chlorophyll a is typically present in higher proportions.

In conclusion, the false statement is option D, which incorrectly states that both chlorophyll a and b are present in equal proportion. Chlorophyll a is the main chief pigment and is more abundant than chlorophyll b in most plants and algae.