Consider the reactions :
(a) `6CO_(2(g))+6H_(2)O_((l))toC_(6)H_(12)O_(6(aq))+6O_(2(g))`
(b) `O_(3(g))+H_(2)O_(2(l))toH_(2)O_((l))+2O_(2(g))`
Why it is more appropriate to write these reactions as :
(a) `6CO_(2(g))+12H_(2)O_((l))toC_(6)H_(12)O_(6(aq))+6H_(2)O_((l))+6O_(2(g))`
(b) `O_(3(g))+H_(2)O_(2(l))toH_(2)O_((l))+O_(2(g))`
Also suggest a technique to investigate the path of the above (a) and (b) redox reactions.

Explanation

(a) Process of photosynthesis is very complex so it occurs in two steps.
Step - 1 : `H_(2)O` decompose in presence of chlorophyll and `H_(2)andO_(2)` is obtained.
Step - 2 : `H_(2)` reduce `CO_(2)` in `C_(6)H_(12)O_(6)` and some molecules of `H_(2)O` are obtained.

We must have to write this equation for total reaction of photosynthesis reaction. So, `12H_(2)O` used for production of 1 mole carbohydrate and `6H_(2)O` produce during this reaction.
(b) `O_(2)` write two times because `O_(2)` is obtained from two different reactants.

For deciding reaction of path (a) `H_(2)O^(18)orH_(2)O` is used.
For deciding reaction of path (b) `H_(2)O_(2)^(18)orO_(3)^(18)` is used.