CONCENTRATION OF HYDROGEN IN WATER The concentration of hydrogen gas (H2) in water is often reported in molarity (moles/liter (M) or milimoles/L mM), parts per million (ppm), parts per billion (ppb), or milligrams per liter (mg/L). In dilute concentrations, 1 ppm is about the sameऔर पढ़ें »जल में हाइड्रोजन की अधिकतम सांद्रता