Question

Chlorophyll b is
A) ${C_{(54)}}{H_{(70)}}{O_6}{N_4}Mg$
B) ${C_{(55)}}{H_{(70)}}Mg{N_4}{O_6}$
C) ${C_{(55)}}{H_{(72)}}{O_5}{N_4}Mg$
D) ${C_{(45)}}{H_{(72)}}{O_5}{N_4}Mg$

Answer 1

Hint: Joseph Bienaime Caventou and Pierre Joseph Pelletier first isolated and named chlorophyll in the year of $1817$. chlorophyll is the green pigment that is responsible for carrying out photosynthesis in plants and also some algae.

Complete answer:
Chlorophyll are of various types but all of them have few common features like the presence of a fifth ring along with four pyrrole rings and also binding property to magnesium. The different subtypes of chlorophyll are- chlorophyll a, b, $c1,\,{\text{c2}}$d and f. Among them the most widely distributed is chlorophyll a and b in plants. The molecular formula of chlorophyll a is ${C_{(55)}}{H_{(72)}}{O_5}{N_4}Mg$ and chlorophyll b is ${C_{(54)}}{H_{(70)}}{O_6}{N_4}Mg$ the rest of the subtypes are more prevalent in algae and cyanobacteria.

Chlorophyll a absorbs blue portion of the electromagnetic spectrum and chlorophyll b absorbs the red portion of the electromagnetic spectrum and both of them reflect green light as a result of which it appears a green pigment. The chlorophyll is found in the photosystems which are embedded in the thylakoid membranes of the chloroplast where they absorb light and gain energy. This energy is then transferred to the photosystems that carry out the reactions of photosynthesis.

So the correct option is (B) ${C_{(55)}}{H_{(70)}}Mg{N_4}{O_6}$

Note: Chlorophyll is very important for green plants, degradation of chlorophyll leads to plant senescence. Another condition where leaves produce insufficient chlorophyll is chlorosis, which may be caused due to deficiency of nutrients or alteration of soil pH or some plant pathogens.