Question

Which of the following represents a balanced chemical equation for photosynthesis?
(A)- $6C{{O}_{2}}+6{{H}_{2}}O\xrightarrow{hv}{{C}_{6}}{{H}_{12}}{{O}_{6}}+6{{O}_{2}}$
(B)- ${{C}_{6}}{{H}_{12}}{{O}_{6}}+6{{O}_{2}}\xrightarrow{hv}6C{{O}_{2}}+6{{H}_{2}}O$
(C)- $6CO+6{{H}_{2}}O\xrightarrow{hv}{{C}_{6}}{{H}_{12}}{{O}_{6}}+3{{O}_{2}}$
 (D)- $6C{{O}_{2}}+6{{H}_{2}}\xrightarrow{hv}{{C}_{6}}{{H}_{12}}{{O}_{6}}+3{{O}_{2}}$

Answer 1

Hint: Photosynthesis is the process of conversion of light energy into chemical energy by plants. The raw materials used in the photosynthesis process are carbon dioxide and water. Glucose is formed as a product with the evolution of ${{O}_{2}}$. This process takes place in the presence of sunlight and chlorophyll.

Complete step by step answer:
The energy requirements of the plants are fulfilled by the process called photosynthesis.
In the presence of sunlight and chlorophyll, plants take carbon dioxide ($C{{O}_{2}}$) from air and water (${{H}_{2}}O$) from soil and convert them into glucose as stored form of energy.
As we are familiar with the molecular formula of glucose, i.e.${{C}_{6}}{{H}_{12}}{{O}_{6}}$. Oxygen (${{O}_{2}}$) is evolved as a by-product during the formation of glucose by photosynthesis.
Thus, the balanced chemical equation representing the process of photosynthesis is written as
     \[6C{{O}_{2}}+6{{H}_{2}}O\xrightarrow{hv}{{C}_{6}}{{H}_{12}}{{O}_{6}}+6{{O}_{2}}\]
Therefore, the correct option is (A).

Now let us see why the other options are incorrect.
Option (B): ${{C}_{6}}{{H}_{12}}{{O}_{6}}+6{{O}_{2}}\xrightarrow{hv}6C{{O}_{2}}+6{{H}_{2}}O$
The reaction given involves the breakdown of glucose into carbon dioxide and water. It is thus, not the right option.

Option (C): $6CO+6{{H}_{2}}O\xrightarrow{hv}{{C}_{6}}{{H}_{12}}{{O}_{6}}+3{{O}_{2}}$
It cannot be the correct answer since the reaction involves the reaction of carbon monoxide and not carbon dioxide with water.

Option (D): $6C{{O}_{2}}+6{{H}_{2}}\xrightarrow{hv}{{C}_{6}}{{H}_{12}}{{O}_{6}}+3{{O}_{2}}$
Carbon dioxide is reacting with hydrogen (${{H}_{2}}$) and not water in the above reaction. Therefore, it cannot be the correct equation for photosynthesis.
So, the correct answer is “Option A”.

Note: Do not get confused between the options. Keep in mind that six moles of carbon dioxide and water are required to produce one mole of glucose and 6 moles of oxygen in presence of sunlight.