Question
Consider the reactions:
Why is it more appropriate to write these reactions as:
Also, suggest a technique to investigate the path of the above (a) and (b) redox reactions.
Solution
(a) Although the mechanism of photosynthesis is very complex but broadly speaking it may be visualised to occur in two steps. In the first step, H2O decomposes to give H2 and O2 in the presence of chlorophyll and H2 thus produced reduces CO2 to C6H12O6 in the second step. During the second step, some H2O molecules are also produced as
Therefore, it is more appropriate, to write the equation for photosynthesis as (3) because it emphasises that 12H2O are used per molecule of carbohydrate formed and 6H2O are produced during the process.
(b) The purpose of writing O2 two times suggests that O2 is being obtained from each of the two reactants.
The path of reactions (a) and (b) can determine by using
in reaction (a) or by using 
Therefore, it is more appropriate, to write the equation for photosynthesis as (3) because it emphasises that 12H2O are used per molecule of carbohydrate formed and 6H2O are produced during the process.
(b) The purpose of writing O2 two times suggests that O2 is being obtained from each of the two reactants.
The path of reactions (a) and (b) can determine by using
in reaction (a) or by using
