Chlorophyll b is a form of chlorophyll. Chlorophyll b helps in photosynthesis by absorbing light energy. Its colour is green and it primarily absorbs blue light. It is insoluble in water and soluble in ethanol, ether. Its molar mass is $907.492 g m o l^{-1}$ and the chemical formula is $C _{55} H _{70} O _{6} N _{4} Mg$.