<Li> 2 H + O + (Catalyst) = 2 H O + (Catalyst) </Li> <P> These chemicals react with water to produce hydrogen and carbon dioxide along with sodium citrate (C H O (COONa)) and water as byproducts (1). Again, hydrogen and oxygen reacting on a catalyst like Palladiumised alumina (supplied separately) combine to form water . </P> <P> The medium, the gas - pak sachet (opened and with water added) and an indicator are placed in an air - tight gas jar which is incubated at the desired temperature . The indicator tells whether the environment was indeed oxygen free or not . </P> <P> The chemical indicator generally used for this purpose is "chemical methylene blue solution" that since synthesis has never been exposed to elemental oxygen . It is colored deep blue on oxidation in presence of atmospheric oxygen in the jar, but will become colorless when oxygen is gone, and anaerobic conditions are achieved . </P>

What is the purpose of the indicator strip in the gaspak system