Only deep botanists can dare to answer????

Question

1) i take a plant, put it in a CO2 lacking jar and place the jar in the sunlight......according to my knowledge the light reaction would take place where as the dark reaction wont.....my question is "am i right".

2) if i collect all the light absorbing pigments from a leaf....then how can i make these pigments absorb sunlight and transfer the energy to water: thus breaking it down?????

Answer 1

1.The dark reaction does not need light and takes place in the presence or absence of light.

2.Use isolated chloroplasts and perform the Hill Reaction (see link)

Answer 2

You are correct in that the light reaction does not require CO2 to proceed but the Calvin cycle (a.k.a., dark reaction) does.

It seems like you're trying to imagine a biological way to produce hydrogen for fuel cells.  This is a great idea.  The problem I can imagine with your second question is that even though the water is broken down and hydrogen is produced, in the chloroplast, the hydrogen ions are immediately used to establish a proton gradient.  If the hydrogen is not immediately used, it will recombine with oxygen.  Also, when the pigments remain in the chloroplast, those hydrogen ions are going to be immediately used to produce ATP.  

You would need to create artificial photosystems (clusters of pigment molecules) outside of the chloroplast and find a way to quickly harvest the hydrogen.

There are people who are working on solar cell nanotechnology to do exactly this.  You should look them up.