I am performing an experiment in which I am taking 35ml 100% ethanol in a small glass tank. I want to reduce this 100% ethanol concentration by a time-dependent chemical reaction. which reaction I can use for this?
There's not enough information to answer your question. How quick do you want the EtOH to degrade (what do you mean by 'time')? Are hazardous chemical a problem (e.g. in a biochemistry application)?
There are 2 possibilities based on the above:
Reaction of Na metal with EtOH to produce hydrogen and sodium ethoxide (quick)
Esterification reaction (slower; needs a catalyst; comes to an equilibrium)