Question

In the process of photosynthesis, $O_2$ gas released from plants comes out from:

• A. $C{O}_2$
• B. $H_{2}O$
• C. both $H_{2}O$ and $C{O}_2$
• D. nothing can be said

Answer 1

Answer: (B)

$H_{2}O$

Photosynthesis is the physico-chemical process by which plants, algae and photosynthetic bacteria use light energy to drive the synthesis of organic compounds. In plants, algae and certain types of bacteria, the photosynthetic process results in the release of molecular oxygen and the removal of carbon dioxide from the atmosphere, that is used to synthesize carbohydrates. The fate of oxygen present in $O_2$ can be found by once using $O^{18}$ atom in water, and then in $C{O}_2$. We will find that Oxygen gas will have $O^{18}$ atoms only when the oxygen of water is changed.
Reaction:
$C{O}_2+H_2{}^{18}\text{O}\underset{chlorophyll}{\overset{hv}{\to }}(C_6{H}_{10}{O}_5{)}_n{+}^{18}{O}_2$