The equilibrium `p-"xyloquinone"+"methylene white"=p-"xylohydroquinone"+"methylene blue"`, may be studied convinently by observing the difference in colour methylene white and methylene blue. One milli- mole of methylene blue was added to `1` litre of solution that was `0.24 M` in `p-"xylohdroquinone"` and `0.012 M` in `p-"xythloquinone"`. It was then found that `4%` of the added methylene blue was reduced to methylene white. What is the equilibrium constant of the above reaction? The equation is balanced with one mole each of `4` substances.