Question

How many electrons are released during the evolution of 1 molecule of $O_2$?

• A. 4
• B. 3
• C. 2
• D. 1

Answer 1

The correct option is A 4

Splitting of $H_{2}O$:- It occurs in the membrane of the thylakoids. When the chloroplasts (chlorophyll pigment containing plastids) are illuminated with light, 2 molecules of $H_{2}O$ are split into 4$H^{+}$, 4$e^{-}$ and 1 $O_2$ is released. These electrons are used to replenish the electrons lost from PS II.
The reaction is as follows
$2H_{2}O\underset{\mathrm{chlorophyll}}{\overset{\mathrm{sunlight}}{\to }}4H^{+}+4e^{-}+O_2$